[mystk96]

which are a better all around head

[96SNAKE]

I hear that the b heads flow alo more than the c heads

[98Cobra_sleeper]

b heads high higher rpm flow. c heads may be the better all around head becaues they create more lower end torque and flow pretty good up top too.

[phoenix99]

B head with 4.10 or 4.30 rear end gears

[zigbigadoru]

actually the c heads flow more than the b heads over every inch of lift. if you would like me to post the numbers then i will but please dear god dont make me do that and just trust my word. its a bitch to type all that up

[mystk96]

Originally Posted by zigbigadoru actually the c heads flow more than the b heads over every inch of lift. if you would like me to post the numbers then i will but please dear god dont make me do that and just trust my word. its a bitch to type all that up

so man how bout those numbers hahah jk jk

i heard B heads flow insanely well just had low velocity air issues but with that yall are sayin i should ditch my b heads for 03 04 c heads

[LGHTNG02GT]

basically what i get is for a good N/A daily driver, C heads will do the trick. if you plan a blower or turbo, B heads would be the better pick. i have a N/A 4v i swapped into my GT with the B heads. to make up for the low air velocity at slower RPM's i got a set of gears to help with that. i plan one day to make a lower intake to put a Termi blower/heat exchanger on this car.

[97_4V_Sleepa]

Originally Posted by zigbigadoru actually the c heads flow more than the b heads over every inch of lift. if you would like me to post the numbers then i will but please dear god dont make me do that and just trust my word. its a bitch to type all that up

Please Do....seriously. I hope you have flow bench numbers to back it up too. HERE LET ME HELP YOU OUT.

REPOST

4V Head Info
________________________________________
B/Swirl Port: (93-97 Lincoln Mark VIII, pre 99 Lincoln Continental, 96-98 Cobra).
The first and only production Ford head with two (square primary, round secondary) intake ports per cylinder, these swirl port castings arrived first in the ’93 Lincoln Mark VIII. Aptly named, due to the way they promoted the incoming air to swirl into the combustion chambers, much like water running down the drain of a once full sink.
Through the years these heads have proven themselves to be excellent high rpm (8000rpm+) performers—mainly in power adder applications--since their tremendous combined intake port cross sectional area and volume (when combined, a full 55cc more than any other 4.6L head design) provide for exceptional power production in the upper regions of the tach. Ironically, it’s those same big, beautiful, twin ports that also prove to be the B head’s largest inherent design flaw. The extra intake port size has a tendency to kill low/mid rpm intake port velocity and power production—hence the use of Ford’s first IMRC (intake manifold runner control) intake on the 96-98 Cobra. By allowing air to reach only one of a B head’s twin intake valves, velocity, and therefore low/mid range torque production was restored in situations under 3250rpm. Later head designs are clearly superior in this regard, which happens to be the one of the most important considerations for those wanting a stout street motor.
There is also some controversy over the single fuel injector/dual intake port setup. Some claim insufficient air/fuel mixing because of the compromised design, however, others contest that the ability to make 1000+rwhp with only minor porting and some form of power adder is testament to the contrary. Whoever you believe, there is little doubt that even after as little as 8,000 miles, carbon and other deposits tend to form on the secondary ports, causing a major airflow impedance, as there is no fuel present to clean them. B heads feature a somewhat small stock exhaust port that really hinders flow in power adder applications. Major gains from porting come with a quality valve job, some pocket and lots of exhaust work. There really isn’t a lot of material to remove from the intake ports themselves.
The Bottom Line: B heads aren’t the best choice for a naturally aspirated street motor. In order to really shine, they need to be paired with a power adder and a short block that can sustain high horsepower and rpm levels. These, the oldest heads, may still be a great choice for full race applications.

Stock Intake Choices: ‘93-‘97 Lincoln Mark VIII, ‘96-‘98 Cobra.
Aftermarket/Modified Stock Intake Choices: HCI, SSR, PHP.
B head dimensions: Combustion Chamber: 52cc, Intake Port Vol.: 107cc primary (square), 115cc secondary (round). Intake Port Entrance: 1.500x1.300” primary (square), 1.660x1.400” secondary (round), Valves: 37mm Int., 30mm Exh.

C/Tumble Port: (99/01 Cobra, 99 Lincoln Continental).
These second-generation Ford DOHC heads feature a single intake port per cylinder with a smaller cross sectional area that boosts incoming airflow velocity compared to previous years. To understand how C heads earn their “tumble port” designation, try to imagine an Olympic high diver doing repetitive front somersaults before cleanly entering a pool at the bottom. This controlled tumble allows for better air/fuel mixing than in the earlier swirl port heads. The new port design allowed for both substantial increases in midrange torque, and superior horsepower production under 8000rpm when compared with earlier heads. Combustion chamber size is also up 2cc.
The design downfall of C heads, and their larger (5.4L Navigator) cousins, is the relatively flat floor and utter lack of a short turn radius in the throat of the intake port. As such, the incoming air tends to overshoot the valves, making the port think the valves are smaller than they actually are. Some ‘99/’01 Cobra owners reported a “ticking/pinging” noise coming from the drivers side head of their cars. This is due to insufficient cooling around the #6, 7, and 8 cylinders that allowed the valves to overheat and therefore seat improperly. Ford remedied the situation by issuing a TSB to remove and replace the affected heads with a version that featured altered coolant flow.
C heads feature a small exhaust port much like Ford’s earlier swirl port heads, but unlike in B heads, both the intake (throat region) and exhaust ports can see extensive porting work. However, removing too much material from the intake port (mouth region) of a tumble port head will kill velocity very quickly, so make sure your head porter knows what they are doing!
The Bottom Line: C heads remain a viable performance upgrade for those looking for more punch in their street driven 4.6L four valve, without having to pay new part prices for the ’03 DOHC or FR500 versions. The increased midrange torque production and greater overall area under the power curve (when compared to swirl port heads) will enhance the performance of a street/strip driven (8,000rpm and under) modular regardless of application.

Stock Intake Choices: ‘99/’01 Cobra, ‘03/’04 Mach 1 & Aviator, ’03 Marauder, FR500.
Aftermarket /Modified Stock Intake Choices: Al Papitto short runner/ported ‘99/’01 Cobra, MP carb/Sullivan intake, FR500, Aviator
C head dimensions: Combustion Chamber: 54cc, Intake Port Vol.: 177cc, Intake Port Entrance: 1.960”x1.350”, Valves: 37mm Int., 30mm Exh.

Navigator: (98+ Lincoln Navigator)
These 5.4L DOHC heads feature essentially the same intake port design as C heads, however they have a much larger intake port volume than 4.6L castings. Despite the fact these heads feature a relatively small exhaust port, the extra intake port volume could be very beneficial in helping fill a motor of greater displacement—think 5.4L. Expect slightly better midrange torque, and sub 8000rpm horsepower production than even C heads, however the larger intake port size leaves a slim selection of intakes to choose from when utilized on a 4.6L block. Forced induction fans take note, Navigator exhaust ports feature a thicker exhaust divider (while keeping the same overall exhaust port size as B,C, and FR500 heads) that allows coolant to circulate through this vital area. Conversely however, the larger divider can also hurt flow by utilizing additional space in the port.
The real downside to Navigator heads, when used on a 4.6L based motor, is the severe limitation they impose on intake selection. The physically larger 5.4L heads don’t leave a lot of room (when installed on a 4.6L block) between them for an intake plenum to sit—though they do bolt right up. Remember that since Navigator intake ports are essentially clones of those of C heads (just on a larger scale), they too suffer from the same intake port flaws that plague the earlier tumble port design--no short turn or floor in the throat of the intake port.
The Bottom Line: The extra port volume the Navi’s possess could be very beneficial in filling a motor with greater than 281 cubic inches of displacement, or in high rpm N/A street/strip or boosted combinations. Fans of boost should remember the cooled exhaust port divider. Lack of intake availability is the real downfall of this otherwise wonderful casting.

Stock Intake Choices: None (4.6L), 98+ Navigator (5.4L)
Aftermarket/Modified Stock Intake Choices: Al Papitto short runner 99 Cobra (4.6L), sheet metal
Navigator head dimensions: Combustion Chamber: 53cc, Intake Port Vol.: 184cc, Intake Port Entrance: 2.290”x1.400”, Valves: 37mm Int., 30mm Exh.

’00 Cobra R: (’00 Cobra R)
Cobra R heads are bar none the best Modular heads available today. However, their extremely scare supply makes them both ridiculously hard to find, and unbelievably expensive.
Initial performance results are understandably hard to obtain, however Al Papitto reports that with only 25hrs of port work into the his new ‘00R heads, they have already eclipsed the performance of his old Navigator heads with months of labor in them. These heads feature larger intake and exhaust ports, +1mm larger exhaust valves, and a dry exhaust port divider. Cobra R heads also require the use of a specific valvetrain not shared with any other modular application due mainly to their overall physically larger size. Al also claims R heads have too much port volume for a street/strip 4.6L application; only consider them with a larger 5.4L motor or a serious 4.6L race application paired with some form of power adder.
The Bottom Line: The best heads you can or can’t find for a Modular four valve motor.
You are as likely to come across a set of these Modular “Godfather” heads as you are to be Brittany Spears’ next uterus masseuse. Though based on their performance abilities, you may want to start saving, just in case…
Stock Intake Choices: None (4.6L), ’00 Cobra R (5.4L)
Aftermarket/Modified Stock Intake Choices: Sheet metal
’00 Cobra R head dimensions: Combustion Chamber: N/A , Intake Port Vol.: N/A , Intake Port Entrance: 2.370”x1.300”, Valves: 37mm Int. 31mm Exh.
Stock Intake Choices: ‘00R
Aftermarket Intake Choices: Sheetmetal.

FR500: (FRPP)
The sole “aftermarket” offering of the bunch, these high flow heads feature a modified C head intake port combined with the smallest port volume of the group—it seems Ford meant to design these heads for high performance naturally aspirated applications. With the same small standard exhaust port as most other DOHC heads you will still have to remove a decent amount of material from the exhaust ports. Port entrance shape/size remains identical to C heads so finding an intake isn’t hard. These heads are capable of producing power beyond 8000rpm, where earlier versions of the tumble port castings begin to lose their luster. FR500 heads are prone to the #6,7, and 8 cylinder cooling problems as well. Major intake port differences between these and earlier tumble port heads include a raised intake port roof, and a real short turn radius that better directs the incoming air into the combustion chamber; not over the valves like in earlier versions of tumble port heads. These heads also feature a dry divider in the exhaust port, which allows for greater flow, but also higher temperatures. Though improved, the heads can still use some TLC from a quality porter to smooth the roughly finished and newly implemented short turn radius, and the standard exhaust treatment.
The Bottom Line: Outstanding performance heads, with exceptional low and mid lift flow capability. The FR500s only real fault is that the newer ’03 DOHC heads provide near identical performance capability (much better on the exhaust side) paired with a cost differential that is approximately two-thirds less than the FRPP castings. Still a great choice for any application, the heads readily pair to a wide variety of stock and aftermarket intakes.
Stock Intake Choices: ‘99/’01 Cobra, ‘03/’04 Mach 1 & Aviator, ’03 Marauder, FR500.
Aftermarket /Modified Stock Intake Choices: Al Papitto short runner/ported ‘99/’01 Cobra, MP/Sullivan carb intake, FR500, Aviator.
FR500 head dimensions: Combustion Chamber: 53cc, Intake Port Vol.: 160cc, Intake Port Entrance: 1.960”x1.350”, Valves: 37mm Int., 30mm Exh.

‘03 DOHC head: (‘03+ Aviator, Marauder, Cobra, Mach 1, Australian Boss 260/290)
Featuring a nearly identical (though 17cc larger in volume due to the fact that they are also used on the much larger Australian Boss 260/290 5.4L DOHCs) intake port to the FR500 head, but combining it with a newly designed, larger and more rectangular exhaust port, these may be the best all around DOHC Ford heads ever manufactured. The improvements made to the intake port shape over previous years include a raised port roof and the introduction of a short radius turn in the throat of the intake port that helps assure the incoming air charge finds the combustion chamber. For those with a forced induction street/strip motor, these are without question the best heads available, and as with the FR500s, they should produce great power up to and beyond 8000rpm regardless of application. ’03 DOHC heads also feature higher quality head castings from the supplier, which is at least partially responsible for the modest increase in flow vs. earlier castings--chalk that up to Ford’s revised quality control standards.
Early runs of the ’03 DOHC head fell victim to the same #6,7,8 cylinder coolant flow problems as earlier tumble port castings. In mid ’03 Ford made a running revision to the ’03 DOHC heads that allowed for more coolant to circulate through the affected areas. A blue mark on the driver’s side head indicates an updated casting, and there are no additional revisions to the ’04 version of this design.
The Bottom Line: On all accounts these are the best modular four valve heads currently available. They combine the exceptional flow of a slightly larger FR500 intake port with a gigantic new rectangular exhaust port.

Stock Intake Choices: ‘99/’01 Cobra, ‘03/’04 Mach 1 & Aviator, ’03 Marauder, FR500.
Aftermarket/Modified Stock Intake Choices: Al Papitto short runner/ported ‘99/’01 Cobra, MP/Sullivan carb intake, FR500, Aviator.
’03 DOHC head dimensions: Combustion Chamber: 52cc, Intake Port Vol.: 177cc, Intake Port Entrance: 1.960”x1.350”, Valves: 37mm Int., 30mm Exh.


In Conclusion
Our panel of experts surmised that aside from the nearly unobtainable ‘00R heads, the ’03 DOHC heads are without question the right choice for your Modular four-valve performance application . The combination of a slightly larger FR500 intake port and modified throat region, coupled with a new larger rectangular exhaust port, and a relatively low price (due to it’s widespread use in the Ford organization) makes the ’03 DOHC casting the current head stud of Ford’s Modular stable.
After porting, the relatively small stock valves/seats become the most serious flow limitation; as such aftermarket replacements should be a serious consideration for those looking to squeeze every last drop of performance from their DOHC heads.

[zigbigadoru]

Originally Posted by 97_4V_Sleepa Please Do....seriously. I hope you have flow bench numbers to back it up too. HERE LET ME HELP YOU OUT. REPOST 4V Head Info ________________________________________ B/Swirl Port: (93-97 Lincoln Mark VIII, pre 99 Lincoln Continental, 96-98 Cobra). The first and only production Ford head with two (square primary, round secondary) intake ports per cylinder, these swirl port castings arrived first in the ’93 Lincoln Mark VIII. Aptly named, due to the way they promoted the incoming air to swirl into the combustion chambers, much like water running down the drain of a once full sink. Through the years these heads have proven themselves to be excellent high rpm (8000rpm+) performers—mainly in power adder applications--since their tremendous combined intake port cross sectional area and volume (when combined, a full 55cc more than any other 4.6L head design) provide for exceptional power production in the upper regions of the tach. Ironically, it’s those same big, beautiful, twin ports that also prove to be the B head’s largest inherent design flaw. The extra intake port size has a tendency to kill low/mid rpm intake port velocity and power production—hence the use of Ford’s first IMRC (intake manifold runner control) intake on the 96-98 Cobra. By allowing air to reach only one of a B head’s twin intake valves, velocity, and therefore low/mid range torque production was restored in situations under 3250rpm. Later head designs are clearly superior in this regard, which happens to be the one of the most important considerations for those wanting a stout street motor. There is also some controversy over the single fuel injector/dual intake port setup. Some claim insufficient air/fuel mixing because of the compromised design, however, others contest that the ability to make 1000+rwhp with only minor porting and some form of power adder is testament to the contrary. Whoever you believe, there is little doubt that even after as little as 8,000 miles, carbon and other deposits tend to form on the secondary ports, causing a major airflow impedance, as there is no fuel present to clean them. B heads feature a somewhat small stock exhaust port that really hinders flow in power adder applications. Major gains from porting come with a quality valve job, some pocket and lots of exhaust work. There really isn’t a lot of material to remove from the intake ports themselves. The Bottom Line: B heads aren’t the best choice for a naturally aspirated street motor. In order to really shine, they need to be paired with a power adder and a short block that can sustain high horsepower and rpm levels. These, the oldest heads, may still be a great choice for full race applications. Stock Intake Choices: ‘93-‘97 Lincoln Mark VIII, ‘96-‘98 Cobra. Aftermarket/Modified Stock Intake Choices: HCI, SSR, PHP. B head dimensions: Combustion Chamber: 52cc, Intake Port Vol.: 107cc primary (square), 115cc secondary (round). Intake Port Entrance: 1.500x1.300” primary (square), 1.660x1.400” secondary (round), Valves: 37mm Int., 30mm Exh. C/Tumble Port: (99/01 Cobra, 99 Lincoln Continental). These second-generation Ford DOHC heads feature a single intake port per cylinder with a smaller cross sectional area that boosts incoming airflow velocity compared to previous years. To understand how C heads earn their “tumble port” designation, try to imagine an Olympic high diver doing repetitive front somersaults before cleanly entering a pool at the bottom. This controlled tumble allows for better air/fuel mixing than in the earlier swirl port heads. The new port design allowed for both substantial increases in midrange torque, and superior horsepower production under 8000rpm when compared with earlier heads. Combustion chamber size is also up 2cc. The design downfall of C heads, and their larger (5.4L Navigator) cousins, is the relatively flat floor and utter lack of a short turn radius in the throat of the intake port. As such, the incoming air tends to overshoot the valves, making the port think the valves are smaller than they actually are. Some ‘99/’01 Cobra owners reported a “ticking/pinging” noise coming from the drivers side head of their cars. This is due to insufficient cooling around the #6, 7, and 8 cylinders that allowed the valves to overheat and therefore seat improperly. Ford remedied the situation by issuing a TSB to remove and replace the affected heads with a version that featured altered coolant flow. C heads feature a small exhaust port much like Ford’s earlier swirl port heads, but unlike in B heads, both the intake (throat region) and exhaust ports can see extensive porting work. However, removing too much material from the intake port (mouth region) of a tumble port head will kill velocity very quickly, so make sure your head porter knows what they are doing! The Bottom Line: C heads remain a viable performance upgrade for those looking for more punch in their street driven 4.6L four valve, without having to pay new part prices for the ’03 DOHC or FR500 versions. The increased midrange torque production and greater overall area under the power curve (when compared to swirl port heads) will enhance the performance of a street/strip driven (8,000rpm and under) modular regardless of application. Stock Intake Choices: ‘99/’01 Cobra, ‘03/’04 Mach 1 & Aviator, ’03 Marauder, FR500. Aftermarket /Modified Stock Intake Choices: Al Papitto short runner/ported ‘99/’01 Cobra, MP carb/Sullivan intake, FR500, Aviator C head dimensions: Combustion Chamber: 54cc, Intake Port Vol.: 177cc, Intake Port Entrance: 1.960”x1.350”, Valves: 37mm Int., 30mm Exh. Navigator: (98+ Lincoln Navigator) These 5.4L DOHC heads feature essentially the same intake port design as C heads, however they have a much larger intake port volume than 4.6L castings. Despite the fact these heads feature a relatively small exhaust port, the extra intake port volume could be very beneficial in helping fill a motor of greater displacement—think 5.4L. Expect slightly better midrange torque, and sub 8000rpm horsepower production than even C heads, however the larger intake port size leaves a slim selection of intakes to choose from when utilized on a 4.6L block. Forced induction fans take note, Navigator exhaust ports feature a thicker exhaust divider (while keeping the same overall exhaust port size as B,C, and FR500 heads) that allows coolant to circulate through this vital area. Conversely however, the larger divider can also hurt flow by utilizing additional space in the port. The real downside to Navigator heads, when used on a 4.6L based motor, is the severe limitation they impose on intake selection. The physically larger 5.4L heads don’t leave a lot of room (when installed on a 4.6L block) between them for an intake plenum to sit—though they do bolt right up. Remember that since Navigator intake ports are essentially clones of those of C heads (just on a larger scale), they too suffer from the same intake port flaws that plague the earlier tumble port design--no short turn or floor in the throat of the intake port. The Bottom Line: The extra port volume the Navi’s possess could be very beneficial in filling a motor with greater than 281 cubic inches of displacement, or in high rpm N/A street/strip or boosted combinations. Fans of boost should remember the cooled exhaust port divider. Lack of intake availability is the real downfall of this otherwise wonderful casting. Stock Intake Choices: None (4.6L), 98+ Navigator (5.4L) Aftermarket/Modified Stock Intake Choices: Al Papitto short runner 99 Cobra (4.6L), sheet metal Navigator head dimensions: Combustion Chamber: 53cc, Intake Port Vol.: 184cc, Intake Port Entrance: 2.290”x1.400”, Valves: 37mm Int., 30mm Exh. ’00 Cobra R: (’00 Cobra R) Cobra R heads are bar none the best Modular heads available today. However, their extremely scare supply makes them both ridiculously hard to find, and unbelievably expensive. Initial performance results are understandably hard to obtain, however Al Papitto reports that with only 25hrs of port work into the his new ‘00R heads, they have already eclipsed the performance of his old Navigator heads with months of labor in them. These heads feature larger intake and exhaust ports, +1mm larger exhaust valves, and a dry exhaust port divider. Cobra R heads also require the use of a specific valvetrain not shared with any other modular application due mainly to their overall physically larger size. Al also claims R heads have too much port volume for a street/strip 4.6L application; only consider them with a larger 5.4L motor or a serious 4.6L race application paired with some form of power adder. The Bottom Line: The best heads you can or can’t find for a Modular four valve motor. You are as likely to come across a set of these Modular “Godfather” heads as you are to be Brittany Spears’ next uterus masseuse. Though based on their performance abilities, you may want to start saving, just in case… Stock Intake Choices: None (4.6L), ’00 Cobra R (5.4L) Aftermarket/Modified Stock Intake Choices: Sheet metal ’00 Cobra R head dimensions: Combustion Chamber: N/A , Intake Port Vol.: N/A , Intake Port Entrance: 2.370”x1.300”, Valves: 37mm Int. 31mm Exh. Stock Intake Choices: ‘00R Aftermarket Intake Choices: Sheetmetal. FR500: (FRPP) The sole “aftermarket” offering of the bunch, these high flow heads feature a modified C head intake port combined with the smallest port volume of the group—it seems Ford meant to design these heads for high performance naturally aspirated applications. With the same small standard exhaust port as most other DOHC heads you will still have to remove a decent amount of material from the exhaust ports. Port entrance shape/size remains identical to C heads so finding an intake isn’t hard. These heads are capable of producing power beyond 8000rpm, where earlier versions of the tumble port castings begin to lose their luster. FR500 heads are prone to the #6,7, and 8 cylinder cooling problems as well. Major intake port differences between these and earlier tumble port heads include a raised intake port roof, and a real short turn radius that better directs the incoming air into the combustion chamber; not over the valves like in earlier versions of tumble port heads. These heads also feature a dry divider in the exhaust port, which allows for greater flow, but also higher temperatures. Though improved, the heads can still use some TLC from a quality porter to smooth the roughly finished and newly implemented short turn radius, and the standard exhaust treatment. The Bottom Line: Outstanding performance heads, with exceptional low and mid lift flow capability. The FR500s only real fault is that the newer ’03 DOHC heads provide near identical performance capability (much better on the exhaust side) paired with a cost differential that is approximately two-thirds less than the FRPP castings. Still a great choice for any application, the heads readily pair to a wide variety of stock and aftermarket intakes. Stock Intake Choices: ‘99/’01 Cobra, ‘03/’04 Mach 1 & Aviator, ’03 Marauder, FR500. Aftermarket /Modified Stock Intake Choices: Al Papitto short runner/ported ‘99/’01 Cobra, MP/Sullivan carb intake, FR500, Aviator. FR500 head dimensions: Combustion Chamber: 53cc, Intake Port Vol.: 160cc, Intake Port Entrance: 1.960”x1.350”, Valves: 37mm Int., 30mm Exh. ‘03 DOHC head: (‘03+ Aviator, Marauder, Cobra, Mach 1, Australian Boss 260/290) Featuring a nearly identical (though 17cc larger in volume due to the fact that they are also used on the much larger Australian Boss 260/290 5.4L DOHCs) intake port to the FR500 head, but combining it with a newly designed, larger and more rectangular exhaust port, these may be the best all around DOHC Ford heads ever manufactured. The improvements made to the intake port shape over previous years include a raised port roof and the introduction of a short radius turn in the throat of the intake port that helps assure the incoming air charge finds the combustion chamber. For those with a forced induction street/strip motor, these are without question the best heads available, and as with the FR500s, they should produce great power up to and beyond 8000rpm regardless of application. ’03 DOHC heads also feature higher quality head castings from the supplier, which is at least partially responsible for the modest increase in flow vs. earlier castings--chalk that up to Ford’s revised quality control standards. Early runs of the ’03 DOHC head fell victim to the same #6,7,8 cylinder coolant flow problems as earlier tumble port castings. In mid ’03 Ford made a running revision to the ’03 DOHC heads that allowed for more coolant to circulate through the affected areas. A blue mark on the driver’s side head indicates an updated casting, and there are no additional revisions to the ’04 version of this design. The Bottom Line: On all accounts these are the best modular four valve heads currently available. They combine the exceptional flow of a slightly larger FR500 intake port with a gigantic new rectangular exhaust port. Stock Intake Choices: ‘99/’01 Cobra, ‘03/’04 Mach 1 & Aviator, ’03 Marauder, FR500. Aftermarket/Modified Stock Intake Choices: Al Papitto short runner/ported ‘99/’01 Cobra, MP/Sullivan carb intake, FR500, Aviator. ’03 DOHC head dimensions: Combustion Chamber: 52cc, Intake Port Vol.: 177cc, Intake Port Entrance: 1.960”x1.350”, Valves: 37mm Int., 30mm Exh. In Conclusion Our panel of experts surmised that aside from the nearly unobtainable ‘00R heads, the ’03 DOHC heads are without question the right choice for your Modular four-valve performance application . The combination of a slightly larger FR500 intake port and modified throat region, coupled with a new larger rectangular exhaust port, and a relatively low price (due to it’s widespread use in the Ford organization) makes the ’03 DOHC casting the current head stud of Ford’s Modular stable. After porting, the relatively small stock valves/seats become the most serious flow limitation; as such aftermarket replacements should be a serious consideration for those looking to squeeze every last drop of performance from their DOHC heads.

you sir are an asshole for making me do this.....and receive neg reps for doing such.


b heads
-------intake-----exhaust
.050---39---------34
.100---79---------71
.150---114---------97
.200---144---------119
.250---172---------132
.300---194---------138
.350---207---------141
.400---217---------144
.450---225---------145
.500---231---------146

c heads
-------intake-----exhaust
.050---40---------34
.100---88---------74
.150---118---------102
.200---151---------123
.250---178---------133
.300---201---------138
.350---211---------140
.400---221---------143
.450---229---------145
.500---233---------145

the c heads match or outflow the b heads on almost every inch of lift. if you have the choice between the b and c heads both for n/a and boost get the c heads if you can. if there is a big price difference in the two get the cheaper one.

[zigbigadoru]

Originally Posted by mystk96 so man how bout those numbers hahah jk jk i heard B heads flow insanely well just had low velocity air issues but with that yall are sayin i should ditch my b heads for 03 04 c heads

nah if you already have those heads dont bother getting the c heads unless you can trade straight up. otherwise it would be an almost non existant difference between the two.

Originally Posted by LGHTNG02GT basically what i get is for a good N/A daily driver, C heads will do the trick. if you plan a blower or turbo, B heads would be the better pick. i have a N/A 4v i swapped into my GT with the B heads. to make up for the low air velocity at slower RPM's i got a set of gears to help with that. i plan one day to make a lower intake to put a Termi blower/heat exchanger on this car.

yes to the gearing for the low velocity but c heads are better period as far as flow goes, and n/a boosted doesnt really matter.

[BWAL]

B heads ftw

[BWAL]

i was thinking about getting C heads, but then i looked in my pants and realized i'm not a little girl

[zigbigadoru]

Originally Posted by BWAL i was thinking about getting C heads, but then i looked in my pants and realized i'm not a little girl

yea? i thought about getting a 4v then i realized who wants to rev? TORQUE!!!!! RAWR!!!!! hehehe

[97_4V_Sleepa]

Originally Posted by zigbigadoru you sir are an asshole for making me do this.....and receive neg reps for doing such. b heads -------intake-----exhaust .050---39---------34 .100---79---------71 .150---114---------97 .200---144---------119 .250---172---------132 .300---194---------138 .350---207---------141 .400---217---------144 .450---225---------145 .500---231---------146 c heads -------intake-----exhaust .050---40---------34 .100---88---------74 .150---118---------102 .200---151---------123 .250---178---------133 .300---201---------138 .350---211---------140 .400---221---------143 .450---229---------145 .500---233---------145 the c heads match or outflow the b heads on almost every inch of lift. if you have the choice between the b and c heads both for n/a and boost get the c heads if you can. if there is a big price difference in the two get the cheaper one.

Just out of pure assholish newb curiosity, Where did you get these numbers? is this with functioning IMRC plates bolted in place on the B heads. Mine are gonna shine with the MMR intake bolted to 'em...damn i have to get out of Iraq

[97_4V_Sleepa]

Originally Posted by zigbigadoru yea? i thought about getting a 4v then i realized who wants to rev? TORQUE!!!!! RAWR!!!!! hehehe

Hater

[acidtonic]

Here is a post I made over at the Corral that sums up my findings nicely.


Without trying to start a war I'd like to see some dyno graphs of a C head car that makes more than 10 horsepower under the curve from 1000rpm-3450rpm over a B head car stock vs stock. Excluding the auto Machs if it mattered.

I've been looking at dyno sheets for the past 2 hours and cant seem to find a C head mach 5spd that truly beats a B head 96-98 Cobra before 3450rpm.

I'll show for reference the B head car has 70K on it and the Mach is under 20K. Also they have the same basic mods besides a better filter in the Mach. So the Cobra should really get stomped right?

Mach has "k&n filter,flow master muffler" @ 19,000 miles
Cobra has "flowmaster mufflers" @ 70,000 miles

http://www.dynoperformance.com/dyno_...=mustang+cobra
http://www.dynoperformance.com/dyno_...=mustang+mach1

I'll also state the AFRs are very close as well as other environmental factors and the inlet temps are 2 degrees apart. The cars are on the same model of dyno too. These are the closest two cases I could find in hours of searching for a somewhat fair set of dynos to compare. On to what I found......

The Mach with C heads doesnt *touch* the aging B head Cobra until 3450rpm where the torque starts to climb over the Cobra.

Up until 3200rpm they are almost identical numbers.
@3200rpm the Cobra is only 1 rwhp\2 rwtq below the Mach.
@3400rpm the Cobra is only 9 rwhp\13 rwtq below the Mach.
@3700rpm the Cobra is only 16 rwhp\23 rwtq below the Mach.
@4000rpm the Cobra is only 19 rwhp\26 rwtq below the Mach.
@4500rpm the Cobra is only 32 rwhp\37 rwtq below the Mach.

(it holds the 30\35 gain until about 5500rpm)
@5500rpm the margin has already dropped back to 20rwhp\20rwtq. Also the AFR is really starting to differ where the Cobra stays a few points richer than the Mach so even then that gain is probably less than 20\20 in reality.

So the low end is supposed to be the strong point of the C heads but I really think it's a midrange setup. Outside of 3400rpm-5500rpm the B head is right with the C head. Now the numbers are higher for the Mach above 5500 but the afrs are not matching any more in favor of the Mach and the power difference isnt too great anyway. So I'd say it's pretty much back on track with the B head within 10hp\10tq if I were to guess by extrapolating the different AFRs.

So really its just a 3000rpm spot of roughly 20-30hp and nothing special outside of that range. In reality it may peak way higher than a B head and look really good on paper. However the effective power band is pretty close except for 3k in the middle. Not to mention less rpm to use beyond the middle since you're a fool not to have shifted yet with the power falling off so quickly. I think once you interpret the graphs it's damn close to the B headed car. Close enough that I wouldn't trade the B's awesome boost potential in addition to all the cost and hassle in swapping. Not to mention B's are "junk" and available for practically free as proven in this very thread. I love cheap replacement parts

Of course more mods and the C's take off, but nearly stock vs stock the B's aren't the dogs they are reputed to be. I believe the gunking up issue is really to blame with many many B head guys not properly cleaning their motors which really cuts into the torque the B's so desperately need to get wound up to make any power.

Sorry for another book but I found this very interesting to investigate

[zigbigadoru]

Originally Posted by 97_4V_Sleepa Just out of pure assholish newb curiosity, Where did you get these numbers? is this with functioning IMRC plates bolted in place on the B heads. Mine are gonna shine with the MMR intake bolted to 'em...damn i have to get out of Iraq

i got those numbers out of my asshole nah its from my 4.6/5.4 engine building book written by sean hyland. no idea if its with imrc plates or not but if i had to guess id say no and it was just on a flow bench

Originally Posted by 97_4V_Sleepa Hater

yep i sure am

Originally Posted by acidtonic Here is a post I made over at the Corral that sums up my findings nicely. Without trying to start a war I'd like to see some dyno graphs of a C head car that makes more than 10 horsepower under the curve from 1000rpm-3450rpm over a B head car stock vs stock. Excluding the auto Machs if it mattered. I've been looking at dyno sheets for the past 2 hours and cant seem to find a C head mach 5spd that truly beats a B head 96-98 Cobra before 3450rpm. I'll show for reference the B head car has 70K on it and the Mach is under 20K. Also they have the same basic mods besides a better filter in the Mach. So the Cobra should really get stomped right? Mach has "k&n filter,flow master muffler" @ 19,000 miles Cobra has "flowmaster mufflers" @ 70,000 miles http://www.dynoperformance.com/dyno_...=mustang+cobra http://www.dynoperformance.com/dyno_...=mustang+mach1 I'll also state the AFRs are very close as well as other environmental factors and the inlet temps are 2 degrees apart. The cars are on the same model of dyno too. These are the closest two cases I could find in hours of searching for a somewhat fair set of dynos to compare. On to what I found...... The Mach with C heads doesnt *touch* the aging B head Cobra until 3450rpm where the torque starts to climb over the Cobra. Up until 3200rpm they are almost identical numbers. @3200rpm the Cobra is only 1 rwhp2 rwtq below the Mach. @3400rpm the Cobra is only 9 rwhp13 rwtq below the Mach. @3700rpm the Cobra is only 16 rwhp23 rwtq below the Mach. @4000rpm the Cobra is only 19 rwhp26 rwtq below the Mach. @4500rpm the Cobra is only 32 rwhp37 rwtq below the Mach. (it holds the 3035 gain until about 5500rpm) @5500rpm the margin has already dropped back to 20rwhp20rwtq. Also the AFR is really starting to differ where the Cobra stays a few points richer than the Mach so even then that gain is probably less than 2020 in reality. So the low end is supposed to be the strong point of the C heads but I really think it's a midrange setup. Outside of 3400rpm-5500rpm the B head is right with the C head. Now the numbers are higher for the Mach above 5500 but the afrs are not matching any more in favor of the Mach and the power difference isnt too great anyway. So I'd say it's pretty much back on track with the B head within 10hp10tq if I were to guess by extrapolating the different AFRs. So really its just a 3000rpm spot of roughly 20-30hp and nothing special outside of that range. In reality it may peak way higher than a B head and look really good on paper. However the effective power band is pretty close except for 3k in the middle. Not to mention less rpm to use beyond the middle since you're a fool not to have shifted yet with the power falling off so quickly. I think once you interpret the graphs it's damn close to the B headed car. Close enough that I wouldn't trade the B's awesome boost potential in addition to all the cost and hassle in swapping. Not to mention B's are "junk" and available for practically free as proven in this very thread. I love cheap replacement parts Of course more mods and the C's take off, but nearly stock vs stock the B's aren't the dogs they are reputed to be. I believe the gunking up issue is really to blame with many many B head guys not properly cleaning their motors which really cuts into the torque the B's so desperately need to get wound up to make any power. Sorry for another book but I found this very interesting to investigate

pretty much what i said except more words there are more factors than simply cfm flow but even so far as limiting the variables to JUST cfm then two heads are practically flowing the same cfm. honestly all of the 4v heads flow within about 10-20cfm of each other and i would say get whichever one you can find the cheapest and ability to mod (including the intake manifold). the only 4v head that is any significantly different is the cobra R heads and obviously those are a bit tricky to find so we can just ignore those.

[mystk96]

Originally Posted by acidtonic Here is a post I made over at the Corral that sums up my findings nicely. Without trying to start a war I'd like to see some dyno graphs of a C head car that makes more than 10 horsepower under the curve from 1000rpm-3450rpm over a B head car stock vs stock. Excluding the auto Machs if it mattered. I've been looking at dyno sheets for the past 2 hours and cant seem to find a C head mach 5spd that truly beats a B head 96-98 Cobra before 3450rpm. I'll show for reference the B head car has 70K on it and the Mach is under 20K. Also they have the same basic mods besides a better filter in the Mach. So the Cobra should really get stomped right? Mach has "k&n filter,flow master muffler" @ 19,000 miles Cobra has "flowmaster mufflers" @ 70,000 miles http://www.dynoperformance.com/dyno_...=mustang+cobra http://www.dynoperformance.com/dyno_...=mustang+mach1 I'll also state the AFRs are very close as well as other environmental factors and the inlet temps are 2 degrees apart. The cars are on the same model of dyno too. These are the closest two cases I could find in hours of searching for a somewhat fair set of dynos to compare. On to what I found...... The Mach with C heads doesnt *touch* the aging B head Cobra until 3450rpm where the torque starts to climb over the Cobra. Up until 3200rpm they are almost identical numbers. @3200rpm the Cobra is only 1 rwhp2 rwtq below the Mach. @3400rpm the Cobra is only 9 rwhp13 rwtq below the Mach. @3700rpm the Cobra is only 16 rwhp23 rwtq below the Mach. @4000rpm the Cobra is only 19 rwhp26 rwtq below the Mach. @4500rpm the Cobra is only 32 rwhp37 rwtq below the Mach. (it holds the 3035 gain until about 5500rpm) @5500rpm the margin has already dropped back to 20rwhp20rwtq. Also the AFR is really starting to differ where the Cobra stays a few points richer than the Mach so even then that gain is probably less than 2020 in reality. So the low end is supposed to be the strong point of the C heads but I really think it's a midrange setup. Outside of 3400rpm-5500rpm the B head is right with the C head. Now the numbers are higher for the Mach above 5500 but the afrs are not matching any more in favor of the Mach and the power difference isnt too great anyway. So I'd say it's pretty much back on track with the B head within 10hp10tq if I were to guess by extrapolating the different AFRs. So really its just a 3000rpm spot of roughly 20-30hp and nothing special outside of that range. In reality it may peak way higher than a B head and look really good on paper. However the effective power band is pretty close except for 3k in the middle. Not to mention less rpm to use beyond the middle since you're a fool not to have shifted yet with the power falling off so quickly. I think once you interpret the graphs it's damn close to the B headed car. Close enough that I wouldn't trade the B's awesome boost potential in addition to all the cost and hassle in swapping. Not to mention B's are "junk" and available for practically free as proven in this very thread. I love cheap replacement parts Of course more mods and the C's take off, but nearly stock vs stock the B's aren't the dogs they are reputed to be. I believe the gunking up issue is really to blame with many many B head guys not properly cleaning their motors which really cuts into the torque the B's so desperately need to get wound up to make any power. Sorry for another book but I found this very interesting to investigate

how would i keep the imrc's clean or just the motor so it doesnt junk up on me

[zigbigadoru]

Originally Posted by mystk96 how would i keep the imrc's clean or just the motor so it doesnt junk up on me

you really cant because there isnt an injector in the little port thing hes talking about to clean out all of the gunk so all you can do is run seafoam or take the heads off and physically clean the gunk out i think. unless that new MMR intake manifold solved the issue of the imrc's and the gunking issue.

[acidtonic]

Use full synthetic oil, change it before it gets dark.

Use seafoam. I made a long post about how to do it exactly on this forum.
Search for the term "seafoam" on all posts by "acidtonic" and you should find it.

I felt a good amount of power come back.... I'd say its about 1-3 times as much power coming back as when you do an oil change that's long over due for reference.