[ModMustang97GT]

So, if I wanted to build a Bad Ass N/A motor. But I wanted to use the 4.6. What would you do. I'm thinking a 13:1 compression. 4v ported aluminum heads, aluminum block with an aftermarket intake and some custom cams. Rev it to 7500 and call it a day. Any one got a guestimate what kind of power that would make. Ported 4V heads are supposed to max around 600hp before needing FI. Anyone know some real life numbers?

[TheBusher]

Would you consider boring & stroking?

[Doc8224]

450-500 with all the supporting bolt on mods. I would bore it out but I wouldn't stroke it. I am building mine and I am gonna run around 11-11.5:1 with P&P heads and manifold, with the bolt on and I will hit 450rwhp.

[mustangmanic]

If you're gonna road race... dont stroke it, that'll be way to much TQ, you want to bore it .20 over... that'll add a lot of hp and some TQ, but mainly HP (what you'll need more of in road racing and auto x).

Bore it .20 over to a 5.0 (i think thats .20 over)... high compression 13:1 is very very very high!!! with that you'll need to run 109+octane constantly and never any bad gas... i would try someting like 12:1, 13:1 is just so risky if not done completely right.

Along with that get stage 3 heads and stage 3 cams... raise that redline up to 7300+ and you'll have a badass road racing machine...

Dont forget suspension, thats the single most important thing in course racing... lower it 2'', upper and lower controll arms (front and rear suspensions), subframe connectors, and racing tires...

Make sure you get a full suspension that is fully adjustable, single most important thing on road racing!

[ModMustang97GT]

This is a pretty much, hypothetical situation. I mean, unless I could get my hands on a 4V block for cheap. I already have essentially the street\track set up from MM right now. I can turn incredibly well. The only thing I have left to buy would be a panhard and lower control arms. Unless I decided to go the Coilover methode and get a torque arm. I could go all out I guess and get the torque arm, coil overs, K-member and A arms. But it doesn't seem all that worth it. I don't get to a track very much. And my handling is already pretty rediculous. What I want, is more power. I already have full exhaust and a CAI. I plan to upgrade my intake to a trickflow with stage 2 heads and cam, if I don't get a custom grind. I would probably leave it at that. If I did decide to pull the short block apart. I'd put in forged parts and possibly go for a modest turbo set up. But then I'd definitely convert to coilovers and get the new K-member. In the end it would be MUCH more expensive. And in all honesty, overkill. Id rather build a purpose built car if I'm going that far. This is a DD after all. But, I would love a monster N/A. Which is what this is all about.
I know I could rev to the moon with race gas a make some crazy ass numbers, but thats not useful. I want to know what a bolt on, not too rediculous N/A 4.6 can do.

[SWEET2KSTANG]

good luck on finding a piston and head combo that will get you to a 13:1 compression. most 4v cars with flat tops will get you to around 12.1 at most. if you have any combustion chamber work on it, then it will go down some more.

[RandoGT]

if you want an N/A monster then you're driving the wrong car man....well, define "monster" then you might be driving the right car

[ModMustang97GT]

You can build any engine to do whatever you want. Its just a question of money. Those F1 engine that make 1000hp are 3.2l v10. Its all how you build it. You could definitely get an insane amount of power out of these engines. Why do you think a Ducati with a 1 Liter engine can make 200hp. Its all in the build. If you use the equation to calculate the max power from a heads flow value. The ported 4v heads are good to 600hp and a good quality intake like a Logan could easily flow enough for that. Then Run a custom set of cams and a new Driveline that would run 7500 rpm. Overboar the cylinder and put in an MSD. All of these things are possible but expensive. I was hoping someone with some imagination had put some effort in to one and could tell me what they have found.

[SWEET2KSTANG]

when you start breaking down each particular bad ass build, it all comes down to physics. you will not make 13:1 compression on a 4.6 with 4v heads, its as simple and realistic as that. if you stroke or big bore, then 13:1 is within reach. like you stated, all about $$$. with the some figures i was comming up with for docs car, i could ring out just over 500 on a +.020 n/a build. thats a dd set up and 91 pump gas. with something that will rev higher and race gas, i could see a hair over 550.

[KingChronic]

as others said, nothing more than flat top pistons, plus you would HAVE to run race fuel all the time with 13:1.

if you dont want to go stroker, get a cobra crank, some light forged I beam rods, flat top pistons, send the heads to fox lake to be ported, get stage 3 cams, get a sullivan intake.

that along with full exhaust, UDP's, a JLT intake could yield nearly 500RWHP. but your only going to have about 375-400FTLBS

[StangAddiction]

I agree with sweet2k..

4v heads with flat tops make 10.5:1 compression....

2v heads with flat tops barely make 12.9...

[ModMustang97GT]

Ok, the whole compression ratio is not an issue. You can easily get dome tops with reliefs cutt in to make that kind of compression. Its just not a stock set up. We run a chevy 511 with 16:1 compression in our Hydro. But, it sounds like the displacement of these engines is the real killer, not the flow. With higher RPM's and custom parts i'm sure you could run some insane numbers, but the cost of doing it all would be too much. It sound like even the more expensive parts that are available are still not enough to put this engine in to the really big numbers.

Any idea how much more a 5.4 would make? and what about a Ls1? I don't think they can do much more than 600 or so n/a. Course I'm not sure about that at all.

[StangAddiction]

The 5.4 wont make a whole lot more power over the 4.6...It'll make a considerable amount more toques though. If you're looking for more top end power, big-bore is the way to go..3.700-in sleeves ...

[Goblin]

Originally Posted by mustangmanic If you're gonna road race... dont stroke it, that'll be way to much TQ, you want to bore it .20 over... that'll add a lot of hp and some TQ, but mainly HP (what you'll need more of in road racing and auto x).

What the hell are you talking about? Too much torque for road racing? Have you ever road raced anything? Actually raced a fast car?

.020 overbore isnt going to add much of anything for horsepower.. so again, what the hell are you talking about? I hope no one is really taking this shyt seriously.

Originally Posted by ModMustang97GT This is a pretty much, hypothetical situation. I mean, unless I could get my hands on a 4V block for cheap.

What is a 4v block?

Originally Posted by ModMustang97GT You can build any engine to do whatever you want. Its just a question of money. Those F1 engine that make 1000hp are 3.2l v10.

Correction, F1 engines displace 2.4L. 950-1000hp @ 19,000rpms

I think your best bet for road racing is a DOHC 5.4, with a set of worked Cobra R heads, and ported R manifold. If your going to spend money, might as well spend it on a 5.4. Getting alot of power out of a 4.6 is just going to be difficult, and time consuming in naturally aspirated trim. There just isnt enough displacement to do it effectively for a daily driven street car.

[ModMustang97GT]

the 4v block and 2v blocks are different. The holes are not the same. In order to put on 4v heads to a 2v block you have to drill new holes and get a bunch of stuff machined. That is why no one swaps the 4v head on to 2v blocks. So, if I could get a 4v (cobra) block...

I'm thinking more and more it just not worth it to mod a mustang as much as getting something else to make a real roadcourse car.

[Goblin]

I dont know where you got that information, but its not true. Modular blocks will share the same heads without *alot* of machining. The bolt configurations are the same, as are the coolant passages. The only major difference is the timing chain covers and their bolt patterns. A very very close friend of mine has a 99 Mustang GT. Its got a 4.6 DOHC, using the stock GT 2v block, and wears 04 maurader heads and intake (same as the mach 1). He didnt have the block re-machined to get the heads to work. The only trouble he had was with the timing chain cover, and some of the accessories. Hes a member of Modular Fords.com. If i remember correctly, his screen name is Faux99Cobra.. or Faux99. Really sweet car.

[mustangmanic]

Originally Posted by Goblin What the hell are you talking about? Too much torque for road racing? Have you ever road raced anything? Actually raced a fast car? .020 overbore isnt going to add much of anything for horsepower.. so again, what the hell are you talking about? I hope no one is really taking this shyt seriously.

Hmmm... lets see what the hell i'm talking about. I FREAKING ROAD RACE! I FREAKING WORK WITH KENNY BROWN! MY DAD's BEEN ROADRACING FOR OVER 20 YEARS! So i know exactly what i'm talking about!!!

Common rule of thumb, you dont stroke a road racing engine... its not the thing to do! Stroke adds much more TQ and Bore adds much more HP, its proven.

You want hp over TQ in road racing (you need TQ, but not as much as you need hp).

IDC what you personally think, its what i freakin know, so dont bash on the true facts pal... cus i know what the hell i'm talking about.

i said, bore .20 over because i have no idea how much you can bore a 4.6L safely... i've heard 302 and i've heard 331 so idk.


A good road racing engine is better left with the stock displacement or a bore (not a stroke). Your RPM's are gonna be above 3k the whole time anyways, if you know how to drive.

and .20 over will add a ton of hp with the right heads and cams...

[mustangmanic]

and if you feel that your car is really really lacking in the TQ department, gears will do it for you... you rarely ever see speeds over 110mph on an publicly open road racing course, so 4.10's would be a great gear.

On my local course (former F1 track at the Indianapolis Motor Speedway) i see speeds in excess of 135, so i'm either sticking with my 3.27's or 3.73's... but with the 3.73's will run out of 4th on the big embanked straight... i already run out of 4th and have to shift into 5th on the straight (not something you want to do while racing).

[StangAddiction]

Originally Posted by mustangmanic Hmmm... lets see what the hell i'm talking about. I FREAKING ROAD RACE! I FREAKING WORK WITH KENNY BROWN! MY DAD's BEEN ROADRACING FOR OVER 20 YEARS! So i know exactly what i'm talking about!!! Common rule of thumb, you dont stroke a road racing engine... its not the thing to do! Stroke adds much more TQ and Bore adds much more HP, its proven. You want hp over TQ in road racing (you need TQ, but not as much as you need hp). IDC what you personally think, its what i freakin know, so dont bash on the true facts pal... cus i know what the hell i'm talking about. i said, bore .20 over because i have no idea how much you can bore a 4.6L safely... i've heard 302 and i've heard 331 so idk. A good road racing engine is better left with the stock displacement or a bore (not a stroke). Your RPM's are gonna be above 3k the whole time anyways, if you know how to drive. and .20 over will add a ton of hp with the right heads and cams...

With a A sleeved block, you can over bore to 3.700-in which makes 304-305 cu.in

and if you're racing..i'd reccomend 3.55s...especially if the engine's modded...

actually, if your road racing a t56 with 3.55 or 3.73 gears would ultimately be better really.

[mustangmanic]

Originally Posted by StangAddiction With a A sleeved block, you can over bore to 3.700-in which makes 304-305 cu.in and if you're racing..i'd reccomend 3.55s...especially if the engine's modded... actually, if your road racing a t56 with 3.55 or 3.73 gears would ultimately be better really.

+1 on a t56. That tranny is absoultly flawless for racing... that paired with 3.73's is 110% perfect!

But for a t3650 of a t45... 3.55's or 3.73's are great