gt 40 iron heads ?

serg · 01-20-2001, 07:42 PM

could any one tell what kind of hp gain can i expect with these pluss there intake to go with it .they are very affordable. i currently have long tube 1 5/8 ,h pipe ,ct back 2 1/2, 373s, t-5 ,new 302 3ooo miles, fender well cold air ind ,flex fan on a 909 gt thanks

NOS_Notch · 01-21-2001, 01:58 AM

My buddy has a '92 GT.....
Iron gt-40's mild port and valve job, stock gt-40 intake, 1.72 r.r's, south sides, 50/50's, 125 shot, 3.73's,,,and some little stuff.
He goes 12.40's on the motor, and 11.40's on the spray.
I think he went from about 13.20 to 12.60 when he did his head change.
When i say "mild" port job that it what i mean.....Alternative in MI, just cleaned up the exhaust side, decked them to get him about 10:1, and valve job(probably $150-$200 total)

------------------
4.10's,long tubes & 75 shot...Goes 12.50's
Check it out at http://www.burnouts.webprovider.com

SaleenGTS · 01-21-2001, 03:19 PM

If you want horsepower, save a little extra money and buy a good set of aluminum heads(AFR,TFS,Canfield...)Those would net you about a 70-80 hp increase with a good Intake(Holley,TFS,Edelbrock RPM)and a good lift cam. The GT-40P's are not good heads IMO. Look at the 93 Cobra, it only dyno's 255 rwhp, and with good heads, intake,and a cam, 300 is attainable. My dad's friend has your setup, but the heads were ported a little meaner, and it maxed out at 265 rwhp with a GT-40 intake. The P's will add about 30 hp, max.

------------------
Dustin
1990 Saleen GTSport #14
TFS Street Heat Upper & Lower(Black), TFS TW heads, TFS 3/8" Phenolic Spacer, E303 Cam, FMS 1.6 Roller Rockers, BBK 70mm TB, FMS 70mm MAF, MAC 1 5/8" Equals, Dynomax Super Turbo 2 1/2" cat back, Bassani 2 1/2" Off-Road X-Pipe, MSD 6AL Ignition w/ MSD TFI Coil, Home made Ram Air, Racecraft Suspension

60ft: 2.158
330ft: 5.396
660ft: 8.271 @ 91.43

1989GT · 01-21-2001, 04:18 PM

Okay saleenGTS we're talking about the GT40's not the GT40P's BIG difference there. Anyway you'll notice a big difference with the heads and intake swap. With that combo you're looking at probably mid-high 12's. If you can port them you'll go even faster. Plus you're probably getting a good deal on the heads so a set of aluminum heads is probably gonna run you atleast $600 dollars more. Ohh and saleen the 93 cobra came with gt40's not gt40p's. Ohh and the trophy stock guys are running in 11's and the factory stock guys and in 12's and drag radials. I would say the GT40's or the GT40P's are a great head. Look at the flow numbers. They're a very good N\A head too. Oh and I bet I can get 30 horses out of my P's with a port job. Just for kicks I'll tell you guys this my car Bone stock ran 15.3 @ 90-91 MPH. With underdrives and cold air it ran 14.9 @ 92 MPH. Now with the mods in my sig. and NO port work look what it runs.

I figure I'm going to port the heads and lower intake and then we'll see what it runs. Oh and those passes we're on BFG drag radials no slicks.

------------------
89GT,T-5Z, D.S.S. 306 shortblock w\main support, B-303 cam, Cobra intake, GT40P heads, 1.72rr, MAC "P" headers, MAC off-road H-Pipe, MAC true-fit w\tips, 373's...and the list goes on!
Throttle Junkie Powered by Ford!
12.824 @ 107.05 MPH

NOS_Notch · 01-21-2001, 07:21 PM

Yep........
Hey '89GT that is pretty inspiring for me.
I have an extrude honed cobra lower and extrude honed upper, getting heads in a few weeks and was hoping to go from 13.20's to 12.70's on motor. I'm pretty sure i can get it by checking out your sig, I just want to be able to get 11's w/ no more than 100 shot.
Sure i hope for more, but don't want to be dissapointed...12.50 on motor?????????????

------------------
4.10's,long tubes & 75 shot...Goes 12.50's
Check it out at http://www.burnouts.webprovider.com

SaleenGTS · 01-21-2001, 08:20 PM

1989 GT-Man, you sound like you know your stuff, and that you think you are King $hit. I hope I never run into you on the street, you and your irons are pretty mean...All I was doing was offering my opinion, and experiences with what I have used. I never said the Cobra had P's, DID YOU READ THE POST? I stated opinions about both the P's and the Cobra heads. All is said was a "if I was in your shoes" Why pay $500 for mediocre heads that will at best flow 230-240 cfm, when you can save and get a good set of heads that will flow 250 stock or 300+ max?? Unless you never plan on swapping heads out again, I'd get a really good set...TFS sells for 900 from Saleen. Don't get me wrong, I think the GT-40's are good heads for a starter, but you will probably want to swap them soon. I have flow charts on heavily ported GT-40 Irons(1.90 i/1.6e valves) at .500 lift they ONLY flowed 208/174. STOCK AFR's flowed 247/186 @ .500...lets think about this heads $500...porting, $200-300. when you are finished you have a $800 pair of fair flowing heads, when you could save a little extra and get the TFS from Saleen that flow 250/190 stock for $900....JUST MY OPINION!!! 1989, if you didn't mean so sound snappy or know-it-allish, I am sorry about my comments, I am in a very bad mood tonight. If you did mean it, then I am not sorry.....and for all you other GT-40 Iron fans out there, I don't mean to bash your heads, I am just offering my opinion

------------------
Dustin
1990 Saleen GTSport #14
TFS Street Heat Upper & Lower(Black), TFS TW heads, TFS 3/8" Phenolic Spacer, E303 Cam, FMS 1.6 Roller Rockers, BBK 70mm TB, FMS 70mm MAF, MAC 1 5/8" Equals, Dynomax Super Turbo 2 1/2" cat back, Bassani 2 1/2" Off-Road X-Pipe, MSD 6AL Ignition w/ MSD TFI Coil, Home made Ram Air, Racecraft Suspension

60ft: 2.158
330ft: 5.396
660ft: 8.271 @ 91.43

1989GT · 01-22-2001, 12:30 AM

Hmmm some how I knew that was coming, I didn't mean to jump your sh!t man. And I'm definitly not the sh!t. You and me both know that you'd beat me in a race...judging by your 1/8 mile time. It's like this sometimes people get their facts messed up, which is easy to do with all the info floating around out there. The way you posted it looked like this, you said the P's aren't good heads IMO. Look at the 93 cobra. I took that as you saying that the cobras had P's. All I'm saying is this. Everybody is sooo quick to jump on aluminum heads these days. When you shouldn't rule out irons. Yeah you save weight. But most al heads don't flow well until you're up in the RPM's so you have no low end at all. And when you compare some of the heads they aren't all that great compared to irons. Everyone wants to compare peak numbers. Which are nice but you have to pass mid-lift twice, everytime the valve opens and shuts. I know people that have slowed down when going from gt 40's to al heads. If all you're gonna do is race then al is probably the way to go. If you don't drop below 4000 RPM and shift at 6200 RPM. But I drive my car every day and it's got tons of low end torque but it pulls hard to the rev-limiter. That's what I was going for. It's a very nice N\A combo. Now if I was going forced induction I would have bought a different head. But I'm looking to spray in the near future and I figure it'll work out well. Well I've gone on long enough. Any more question or comments and I'll try my best to help\answer them.

------------------
89GT,T-5Z, D.S.S. 306 shortblock w\main support, B-303 cam, Cobra intake, GT40P heads, 1.72rr, MAC "P" headers, MAC off-road H-Pipe, MAC true-fit w\tips, 373's...and the list goes on!
Throttle Junkie Powered by Ford!
12.824 @ 107.05 MPH

SaleenGTS · 01-22-2001, 10:30 AM

1989-Like I said, if you didn't mean to be rude, I am sorry, and indeed I am sorry. After I replied, I re-read my post and saw that what I said could be confusing, and I am sorry for that too. I completely understand your theory on the Iron's streetability. That is my opinion too, like I said, If max hp is what you want, then Alum. is the way to go. Ironically enough though, my power curve on my dyno hit 325 rwtq at 3500, and peaked out at 337@4600. so as you can see the TW's are good all range heads, but that is IMO. Irons are great for low rpm street heads, but can only take you so far, just like you stated. No hard feelings?

BTW, 107 is a awesome speed out of those un-ported GT40's...peace

------------------
Dustin
1990 Saleen GTSport #14
TFS Street Heat Upper & Lower(Black), TFS TW heads, TFS 3/8" Phenolic Spacer, E303 Cam, FMS 1.6 Roller Rockers, BBK 70mm TB, FMS 70mm MAF, MAC 1 5/8" Equals, Dynomax Super Turbo 2 1/2" cat back, Bassani 2 1/2" Off-Road X-Pipe, MSD 6AL Ignition w/ MSD TFI Coil, Home made Ram Air, Racecraft Suspension

60ft: 2.158
330ft: 5.396
660ft: 8.271 @ 91.43

1989GT · 01-22-2001, 11:58 AM

Thanks man! No hard feelings. Sounds like you've got the best of both worlds with that combo. I think that intake spacer is helping you out in the low end torque department.

Somebody needs to book mark this page... it's got a lot of good info.

------------------
89GT,T-5Z, D.S.S. 306 shortblock w\main support, B-303 cam, Cobra intake, GT40P heads, 1.72rr, MAC "P" headers, MAC off-road H-Pipe, MAC true-fit w\tips, 373's...and the list goes on!
Throttle Junkie Powered by Ford!
12.824 @ 107.05 MPH

NOS_Notch · 01-22-2001, 09:11 PM

Dang..i think one of you might need a pregnancy test afetr that make-up!!!!
Just kidding...
What is an 8.27 1/8th????about a 12.00???
And i thought you were saying cobra's had p-heads too.

------------------
4.10's,long tubes & 75 shot...Goes 12.50's
Check it out at http://www.burnouts.webprovider.com

Hethj7 · 01-22-2001, 09:51 PM

I'm feeling the love here guys!!

skiwesser · 01-23-2001, 01:40 AM

Hey Saleen,
You must be runnin' on street tires with
2.158 60' & 8.27@91.43? 1/8 Mi.
Throw some stock 4-cyl springs(if your racecraft's won't give you room) & D.R's for a night & see what she'll really do!!
I like your engine combo!My best 60' is a 1.95 on TOO tall D.R.'s (27.5") with a basicly stock motor, tired too!

Wish I had MONEY !!! NEED it for SPEED!!!

------------------
88 GT subs,pullies,1 1/2 shorties,F.M.,3.73's,PRO 5.0 shifter,140,000 miles 8.881@78.09
Mcreary drag radials

[This message has been edited by skiwesser (edited 01-23-2001).]

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01-20-2001, 07:42 PM	#1
serg Registered Member Join Date: Jul 2000 Location: junction city ks usa Posts: 29	gt 40 iron heads ? could any one tell what kind of hp gain can i expect with these pluss there intake to go with it .they are very affordable. i currently have long tube 1 5/8 ,h pipe ,ct back 2 1/2, 373s, t-5 ,new 302 3ooo miles, fender well cold air ind ,flex fan on a 909 gt thanks

01-21-2001, 01:58 AM	#2
NOS_Notch Registered Member Join Date: Sep 2000 Location: Fresno,CA. USA Posts: 384	My buddy has a '92 GT..... Iron gt-40's mild port and valve job, stock gt-40 intake, 1.72 r.r's, south sides, 50/50's, 125 shot, 3.73's,,,and some little stuff. He goes 12.40's on the motor, and 11.40's on the spray. I think he went from about 13.20 to 12.60 when he did his head change. When i say "mild" port job that it what i mean.....Alternative in MI, just cleaned up the exhaust side, decked them to get him about 10:1, and valve job(probably $150-$200 total) ------------------ 4.10's,long tubes & 75 shot...Goes 12.50's Check it out at http://www.burnouts.webprovider.com

01-21-2001, 03:19 PM	#3
SaleenGTS RICE taste like Chicken Join Date: Jun 2000 Location: Edmond, OK Posts: 687	If you want horsepower, save a little extra money and buy a good set of aluminum heads(AFR,TFS,Canfield...)Those would net you about a 70-80 hp increase with a good Intake(Holley,TFS,Edelbrock RPM)and a good lift cam. The GT-40P's are not good heads IMO. Look at the 93 Cobra, it only dyno's 255 rwhp, and with good heads, intake,and a cam, 300 is attainable. My dad's friend has your setup, but the heads were ported a little meaner, and it maxed out at 265 rwhp with a GT-40 intake. The P's will add about 30 hp, max. ------------------ Dustin 1990 Saleen GTSport #14 TFS Street Heat Upper & Lower(Black), TFS TW heads, TFS 3/8" Phenolic Spacer, E303 Cam, FMS 1.6 Roller Rockers, BBK 70mm TB, FMS 70mm MAF, MAC 1 5/8" Equals, Dynomax Super Turbo 2 1/2" cat back, Bassani 2 1/2" Off-Road X-Pipe, MSD 6AL Ignition w/ MSD TFI Coil, Home made Ram Air, Racecraft Suspension 60ft: 2.158 330ft: 5.396 660ft: 8.271 @ 91.43

01-21-2001, 04:18 PM	#4
1989GT Registered Member Join Date: Apr 1999 Location: Cincinnati,OH Posts: 1,511	Okay saleenGTS we're talking about the GT40's not the GT40P's BIG difference there. Anyway you'll notice a big difference with the heads and intake swap. With that combo you're looking at probably mid-high 12's. If you can port them you'll go even faster. Plus you're probably getting a good deal on the heads so a set of aluminum heads is probably gonna run you atleast $600 dollars more. Ohh and saleen the 93 cobra came with gt40's not gt40p's. Ohh and the trophy stock guys are running in 11's and the factory stock guys and in 12's and drag radials. I would say the GT40's or the GT40P's are a great head. Look at the flow numbers. They're a very good N\A head too. Oh and I bet I can get 30 horses out of my P's with a port job. Just for kicks I'll tell you guys this my car Bone stock ran 15.3 @ 90-91 MPH. With underdrives and cold air it ran 14.9 @ 92 MPH. Now with the mods in my sig. and NO port work look what it runs. I figure I'm going to port the heads and lower intake and then we'll see what it runs. Oh and those passes we're on BFG drag radials no slicks. ------------------ 89GT,T-5Z, D.S.S. 306 shortblock w\main support, B-303 cam, Cobra intake, GT40P heads, 1.72rr, MAC "P" headers, MAC off-road H-Pipe, MAC true-fit w\tips, 373's...and the list goes on! Throttle Junkie Powered by Ford! 12.824 @ 107.05 MPH

01-21-2001, 07:21 PM	#5
NOS_Notch Registered Member Join Date: Sep 2000 Location: Fresno,CA. USA Posts: 384	Yep........ Hey '89GT that is pretty inspiring for me. I have an extrude honed cobra lower and extrude honed upper, getting heads in a few weeks and was hoping to go from 13.20's to 12.70's on motor. I'm pretty sure i can get it by checking out your sig, I just want to be able to get 11's w/ no more than 100 shot. Sure i hope for more, but don't want to be dissapointed...12.50 on motor????????????? ------------------ 4.10's,long tubes & 75 shot...Goes 12.50's Check it out at http://www.burnouts.webprovider.com

01-21-2001, 08:20 PM	#6
SaleenGTS RICE taste like Chicken Join Date: Jun 2000 Location: Edmond, OK Posts: 687	1989 GT-Man, you sound like you know your stuff, and that you think you are King $hit. I hope I never run into you on the street, you and your irons are pretty mean...All I was doing was offering my opinion, and experiences with what I have used. I never said the Cobra had P's, DID YOU READ THE POST? I stated opinions about both the P's and the Cobra heads. All is said was a "if I was in your shoes" Why pay $500 for mediocre heads that will at best flow 230-240 cfm, when you can save and get a good set of heads that will flow 250 stock or 300+ max?? Unless you never plan on swapping heads out again, I'd get a really good set...TFS sells for 900 from Saleen. Don't get me wrong, I think the GT-40's are good heads for a starter, but you will probably want to swap them soon. I have flow charts on heavily ported GT-40 Irons(1.90 i/1.6e valves) at .500 lift they ONLY flowed 208/174. STOCK AFR's flowed 247/186 @ .500...lets think about this heads $500...porting, $200-300. when you are finished you have a $800 pair of fair flowing heads, when you could save a little extra and get the TFS from Saleen that flow 250/190 stock for $900....JUST MY OPINION!!! 1989, if you didn't mean so sound snappy or know-it-allish, I am sorry about my comments, I am in a very bad mood tonight. If you did mean it, then I am not sorry.....and for all you other GT-40 Iron fans out there, I don't mean to bash your heads, I am just offering my opinion ------------------ Dustin 1990 Saleen GTSport #14 TFS Street Heat Upper & Lower(Black), TFS TW heads, TFS 3/8" Phenolic Spacer, E303 Cam, FMS 1.6 Roller Rockers, BBK 70mm TB, FMS 70mm MAF, MAC 1 5/8" Equals, Dynomax Super Turbo 2 1/2" cat back, Bassani 2 1/2" Off-Road X-Pipe, MSD 6AL Ignition w/ MSD TFI Coil, Home made Ram Air, Racecraft Suspension 60ft: 2.158 330ft: 5.396 660ft: 8.271 @ 91.43

01-22-2001, 12:30 AM	#7
1989GT Registered Member Join Date: Apr 1999 Location: Cincinnati,OH Posts: 1,511	Hmmm some how I knew that was coming, I didn't mean to jump your sh!t man. And I'm definitly not the sh!t. You and me both know that you'd beat me in a race...judging by your 1/8 mile time. It's like this sometimes people get their facts messed up, which is easy to do with all the info floating around out there. The way you posted it looked like this, you said the P's aren't good heads IMO. Look at the 93 cobra. I took that as you saying that the cobras had P's. All I'm saying is this. Everybody is sooo quick to jump on aluminum heads these days. When you shouldn't rule out irons. Yeah you save weight. But most al heads don't flow well until you're up in the RPM's so you have no low end at all. And when you compare some of the heads they aren't all that great compared to irons. Everyone wants to compare peak numbers. Which are nice but you have to pass mid-lift twice, everytime the valve opens and shuts. I know people that have slowed down when going from gt 40's to al heads. If all you're gonna do is race then al is probably the way to go. If you don't drop below 4000 RPM and shift at 6200 RPM. But I drive my car every day and it's got tons of low end torque but it pulls hard to the rev-limiter. That's what I was going for. It's a very nice N\A combo. Now if I was going forced induction I would have bought a different head. But I'm looking to spray in the near future and I figure it'll work out well. Well I've gone on long enough. Any more question or comments and I'll try my best to help\answer them. ------------------ 89GT,T-5Z, D.S.S. 306 shortblock w\main support, B-303 cam, Cobra intake, GT40P heads, 1.72rr, MAC "P" headers, MAC off-road H-Pipe, MAC true-fit w\tips, 373's...and the list goes on! Throttle Junkie Powered by Ford! 12.824 @ 107.05 MPH

01-22-2001, 10:30 AM	#8
SaleenGTS RICE taste like Chicken Join Date: Jun 2000 Location: Edmond, OK Posts: 687	1989-Like I said, if you didn't mean to be rude, I am sorry, and indeed I am sorry. After I replied, I re-read my post and saw that what I said could be confusing, and I am sorry for that too. I completely understand your theory on the Iron's streetability. That is my opinion too, like I said, If max hp is what you want, then Alum. is the way to go. Ironically enough though, my power curve on my dyno hit 325 rwtq at 3500, and peaked out at 337@4600. so as you can see the TW's are good all range heads, but that is IMO. Irons are great for low rpm street heads, but can only take you so far, just like you stated. No hard feelings? BTW, 107 is a awesome speed out of those un-ported GT40's...peace ------------------ Dustin 1990 Saleen GTSport #14 TFS Street Heat Upper & Lower(Black), TFS TW heads, TFS 3/8" Phenolic Spacer, E303 Cam, FMS 1.6 Roller Rockers, BBK 70mm TB, FMS 70mm MAF, MAC 1 5/8" Equals, Dynomax Super Turbo 2 1/2" cat back, Bassani 2 1/2" Off-Road X-Pipe, MSD 6AL Ignition w/ MSD TFI Coil, Home made Ram Air, Racecraft Suspension 60ft: 2.158 330ft: 5.396 660ft: 8.271 @ 91.43

01-22-2001, 11:58 AM	#9
1989GT Registered Member Join Date: Apr 1999 Location: Cincinnati,OH Posts: 1,511	Thanks man! No hard feelings. Sounds like you've got the best of both worlds with that combo. I think that intake spacer is helping you out in the low end torque department. Somebody needs to book mark this page... it's got a lot of good info. ------------------ 89GT,T-5Z, D.S.S. 306 shortblock w\main support, B-303 cam, Cobra intake, GT40P heads, 1.72rr, MAC "P" headers, MAC off-road H-Pipe, MAC true-fit w\tips, 373's...and the list goes on! Throttle Junkie Powered by Ford! 12.824 @ 107.05 MPH

01-22-2001, 09:11 PM	#10
NOS_Notch Registered Member Join Date: Sep 2000 Location: Fresno,CA. USA Posts: 384	Dang..i think one of you might need a pregnancy test afetr that make-up!!!! Just kidding... What is an 8.27 1/8th????about a 12.00??? And i thought you were saying cobra's had p-heads too. ------------------ 4.10's,long tubes & 75 shot...Goes 12.50's Check it out at http://www.burnouts.webprovider.com

01-22-2001, 09:51 PM	#11
Hethj7 Mizzou Tigers Join Date: Apr 1999 Location: weston, MO United States Posts: 1,455	I'm feeling the love here guys!!

01-23-2001, 01:40 AM	#12
skiwesser Registered Member Join Date: Sep 2000 Location: rock hill,S.C. 29730 Posts: 420	Hey Saleen, You must be runnin' on street tires with 2.158 60' & 8.27@91.43? 1/8 Mi. Throw some stock 4-cyl springs(if your racecraft's won't give you room) & D.R's for a night & see what she'll really do!! I like your engine combo!My best 60' is a 1.95 on TOO tall D.R.'s (27.5") with a basicly stock motor, tired too! Wish I had MONEY !!! NEED it for SPEED!!! ------------------ 88 GT subs,pullies,1 1/2 shorties,F.M.,3.73's,PRO 5.0 shifter,140,000 miles 8.881@78.09 Mcreary drag radials [This message has been edited by skiwesser (edited 01-23-2001).]