Heads?

1989Gt. · May 17th, 2009, 05:16 PM

Ok so i was looking into getting new heads the gt-40 any of them they all give about the same hp increase from what im hearing. Anyways my question is this... When i change my heads with the gt40 heads will i still be able to pass smog with out any issues or changes.... or what will happen will it be better?

Also i have another question before i buy these what cc and all that should i get or does it realy matter?

I have a basically stock motor just bolt ons. I will change my throttle body to a 70mm and my maf to a 70mm prob thats what im going to do...

Ill also be changing my Upper and lower intake to the explorer one as well maybe the trickflow not sure which one i will be purchasing, yet.

White Thunder · May 17th, 2009, 06:09 PM

the gt 40's came on the 93 cobra....considering they passed you should be fine

1slo5.0 · May 17th, 2009, 08:48 PM

Originally Posted by 1989Gt.

Ok so i was looking into getting new heads the gt-40 any of them they all give about the same hp increase from what im hearing. Anyways my question is this... When i change my heads with the gt40 heads will i still be able to pass smog with out any issues or changes.... or what will happen will it be better?

Also i have another question before i buy these what cc and all that should i get or does it realy matter?

I have a basically stock motor just bolt ons. I will change my throttle body to a 70mm and my maf to a 70mm prob thats what im going to do...

Ill also be changing my Upper and lower intake to the explorer one as well maybe the trickflow not sure which one i will be purchasing, yet.

You will have no issues passing the sniffer test with those heads. One thing to look into is combustion chamber size. I'm not sure if the chamber size is different between the GT40 heads on the early V8 Explorers and the 93-95 Cobras but I know the Explorer GT40 heads have 65cc chambers. The GT40P heads have 61cc chambers. The 65cc chambers will drop your compression ratio to about 8.6:1 unless you have the heads milled. I would not recommend dropping an already low compression ratio any lower. If you get a set of P heads and have them milled you can raise the compression ratio to about 10:1. The P heads flow slightly more air too. The Explorer intake is a good choice.

coreyflipp · May 17th, 2009, 10:33 PM

Originally Posted by 1slo5.0

If you get a set of P heads and have them milled you can raise the compression ratio to about 10:1.

Darrel, how much needs to be shaved off the gt40p's to get 10 to 1. Is this with stock pistons. And what head gasket?

1slo5.0 · May 17th, 2009, 10:38 PM

Originally Posted by coreyflipp

Darrel, how much needs to be shaved off the gt40p's to get 10 to 1. Is this with stock pistons. And what head gasket?

I believe .030 but I don't remember for sure. A machine shop will be able to tell you.

JBIGBOOTSY · May 18th, 2009, 12:46 AM

Originally Posted by 1slo5.0

I believe .030 but I don't remember for sure. A machine shop will be able to tell you.

I used to have all the info, but I lost it. .030" mill was a hair under 10:1 with a .042, or .040 gasket. I cant remember.

1989Gt. · May 18th, 2009, 12:54 AM

ok i understang so if i get the gt40p heads i wont have to get them milled?

JBIGBOOTSY · May 18th, 2009, 01:10 AM

Originally Posted by 1989Gt.

ok i understang so if i get the gt40p heads i wont have to get them milled?

If the surface is true, no.

Iwannagofast · May 18th, 2009, 02:29 AM

i think it was the regular gt40s that would really need to be milled because of the larger combustion chamber

1989Gt. · May 18th, 2009, 03:22 AM

what about the gt40x heads

1slo5.0 · May 18th, 2009, 09:13 AM

Originally Posted by 1989Gt.

ok i understang so if i get the gt40p heads i wont have to get them milled?

I'd have them resurfaced no matter what just to make sure you have a good sealing surface. That won't require much material be removed.

1slo5.0 · May 18th, 2009, 09:16 AM

Originally Posted by 1989Gt.

what about the gt40x heads

They have a 64cc chamber. You might want to cut them down a bit too.

Why not get some real heads? If you are going to pay for a GT40X head, why not get a Trick Flow, AFR, etc?

95StangMX · May 18th, 2009, 03:48 PM

Originally Posted by 1slo5.0

I'd have them resurfaced no matter what just to make sure you have a good sealing surface. That won't require much material be removed.

Originally Posted by 1slo5.0

They have a 64cc chamber. You might want to cut them down a bit too.
+1

Why not get some real heads? If you are going to pay for a GT40X head, why not get a Trick Flow, AFR, etc?

any head you buy should be magnafluxed and like darrell said shave em down to make sure you have a good flat clean surface to make the seal.. and unless you find someone giving away a set ot 40x heads they are not worth it you would be well on your way to a set of TW's for the prices they are going for. You go with the 40's or the 40p's I would get them shaved, magnafluxed to check for cracks, valve job, and springs at the least...

1989Gt. · May 18th, 2009, 04:38 PM

Well how much better are the trick flow ones cause i was looking at them too.... i can get them of of ebay OH and i was looking at a trickflow intake toady whats the streetburner set? Is it good

1slo5.0 · May 18th, 2009, 04:49 PM

Originally Posted by 1989Gt.

Well how much better are the trick flow ones cause i was looking at them too.... i can get them of of ebay OH and i was looking at a trickflow intake toady whats the streetburner set? Is it good

Trick Flow heads are much better than any GT40 head.

1989Gt. · May 18th, 2009, 04:51 PM

What about the intake? i saw a upper and lower intake streetburner set for 100 bucks used but in perfect condition. from what i saw good deal better then the gt40 intake?

95StangMX · May 18th, 2009, 05:00 PM

yeah 100 bills is a great deal for upper and lower.......shit thats a steal....I would snatch it up b4 its gone...and its not old at all cause they just started calling them the street burner they were the street heat b4, unless they just are saying that in the ad to make it seem newer...but still a good deal

1989Gt. · May 18th, 2009, 05:09 PM

ok causei was like thats the street burner ones ok it looks new but it is used but still is it better then the cobra one like the actual cobra one cause i was looking at one that was brand new dude wants 170 for it it has the 70mm throttle body maf and rails and injectors too. to match

95StangMX · May 18th, 2009, 05:20 PM

That cobra one doesnt sound like a bad deal but what brand of TB and what injectors....I payed almost 400 bucks just for my 30 lb. injectors.....I am a little leary of buying used injectors but you can always take them and have them cleaned and checked but for 170 for the intakes TB's and maf isnt bad either depending on the brand and condition....

baine21225 · May 18th, 2009, 05:28 PM

i'd grab the TF intake

May 17th, 2009, 05:16 PM	#1
1989Gt. Hardcore Enthusiast 1989 Mustang GT Join Date: Apr 2008 Posts: 2,797 iTrader: 0 reviews	Heads? Ok so i was looking into getting new heads the gt-40 any of them they all give about the same hp increase from what im hearing. Anyways my question is this... When i change my heads with the gt40 heads will i still be able to pass smog with out any issues or changes.... or what will happen will it be better? Also i have another question before i buy these what cc and all that should i get or does it realy matter? I have a basically stock motor just bolt ons. I will change my throttle body to a 70mm and my maf to a 70mm prob thats what im going to do... Ill also be changing my Upper and lower intake to the explorer one as well maybe the trickflow not sure which one i will be purchasing, yet.

May 18th, 2009, 05:00 PM	#17
95StangMX MM Fanatic 95 Mustang GT depends how many people are pushing Join Date: Oct 2007 Location: Playa del Carmen, Mexico Posts: 3,243 iTrader: 0 reviews	yeah 100 bills is a great deal for upper and lower.......shit thats a steal....I would snatch it up b4 its gone...and its not old at all cause they just started calling them the street burner they were the street heat b4, unless they just are saying that in the ad to make it seem newer...but still a good deal __________________ People should think about boarding up their glass house before starting a rock fight!

May 18th, 2009, 05:20 PM	#19
95StangMX MM Fanatic 95 Mustang GT depends how many people are pushing Join Date: Oct 2007 Location: Playa del Carmen, Mexico Posts: 3,243 iTrader: 0 reviews	That cobra one doesnt sound like a bad deal but what brand of TB and what injectors....I payed almost 400 bucks just for my 30 lb. injectors.....I am a little leary of buying used injectors but you can always take them and have them cleaned and checked but for 170 for the intakes TB's and maf isnt bad either depending on the brand and condition.... __________________ People should think about boarding up their glass house before starting a rock fight!

May 18th, 2009, 05:28 PM	#20
baine21225 MM Fanatic Join Date: Jun 2007 Location: Baltimore, MD Posts: 4,349 iTrader: 1 reviews	i'd grab the TF intake __________________ "That's how Dad did it, that's how America does it... and it's worked out pretty well so far..."

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May 18th, 2009, 12:54 AM	#7
1989Gt. Hardcore Enthusiast 1989 Mustang GT Join Date: Apr 2008 Posts: 2,797 iTrader: 0 reviews	ok i understang so if i get the gt40p heads i wont have to get them milled?

May 18th, 2009, 03:22 AM	#10
1989Gt. Hardcore Enthusiast 1989 Mustang GT Join Date: Apr 2008 Posts: 2,797 iTrader: 0 reviews	what about the gt40x heads

May 18th, 2009, 04:38 PM	#14
1989Gt. Hardcore Enthusiast 1989 Mustang GT Join Date: Apr 2008 Posts: 2,797 iTrader: 0 reviews	Well how much better are the trick flow ones cause i was looking at them too.... i can get them of of ebay OH and i was looking at a trickflow intake toady whats the streetburner set? Is it good

May 18th, 2009, 04:51 PM	#16
1989Gt. Hardcore Enthusiast 1989 Mustang GT Join Date: Apr 2008 Posts: 2,797 iTrader: 0 reviews	What about the intake? i saw a upper and lower intake streetburner set for 100 bucks used but in perfect condition. from what i saw good deal better then the gt40 intake?

May 18th, 2009, 05:09 PM	#18
1989Gt. Hardcore Enthusiast 1989 Mustang GT Join Date: Apr 2008 Posts: 2,797 iTrader: 0 reviews	ok causei was like thats the street burner ones ok it looks new but it is used but still is it better then the cobra one like the actual cobra one cause i was looking at one that was brand new dude wants 170 for it it has the 70mm throttle body maf and rails and injectors too. to match

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