Official GT40P headed 300rwhp thread!!!

tmoss · Aug 12, 2008

they look good - ought to make a real nice street head.

GTA_V6_Mustang · Aug 12, 2008

tmoss said:
they look good - ought to make a real nice street head.

what do you usually get out of them, The most I have seen is 230cfm

tmoss · Aug 12, 2008

That'a about what you'll see from most good porters - and it will make some good power in the 220-230cfm range.

fastgtfairlane · Aug 12, 2008

killer95stang, your dyno sheet its nice. your car makes really good power and has a nice torque curve throughout the powerband too. need new videos asap. wanna hear that dr gas x pipe again with bullets.

hollywoodstang · Aug 21, 2008

What is this Neil Erickson guys contact info? How do you get hold of him? Anyone have his contact info?

Thanks

foxbdy88 · Dec 18, 2008

Hey guys whats up? I too am working with a set of Iron GT40's. Im gonna be running a TFS1 cam and a TFS spring kit on my heads and do some mild porting on the exhaust side of them.

So heres is my Question, Reading through many forums i have learned and been confused several times. The GT40 non P heads which I have, have larger combustion chambers correct? Ive read 65cc and I would like to bump compression a little possible 9.5/8/ or 10:1 depndeing on what i need to do. So please lead me in the right direction.

How much do they need to milled?
What modifactions will i have to do?
Size of push rods?

I want to use pedestal RR's but which size?

Im freshening up the block and bottom end and using the stock pistons

Pokageek · Dec 19, 2008

tmoss said:
If you put your car up for any period this winter, port that stock lower intake for another nice hit in power. Instructions on how to do it yourself are on my website.

I had a 306 too. Either that or go TRACK heat Trick flow intake. When I went from the stock intake to street heat -> it was a MAJOR difference in power. Then when I got my gears (u need them) I added the track heat and it revved out like a 32 valve cobra and still had GREAT low end! Totally different car and much better power! Good luck.

95_5.0@15 · Dec 21, 2008

mojave · Feb 4, 2009

I'm going to bring this thread back from the dead... Can't let it get buried!

Chern_889 · Feb 4, 2009

I can not wait until spring time rolls around to get some seat time with my new-to-me GT40P heads, and its definatly going to get some dyno time

Pokageek · Feb 4, 2009

NotQuik · Feb 5, 2009

GTA_V6_Mustang said:
You guys can add me to this list as well. I Already had the cobra manifold fully ported and now am having the heads race ported, this is where they are at right now

lift value .100 .200 .300 .400 .500 .600

stock 58 121 159 186 190 195

yours as delivered 59 118 161 191 190 195

ported 60 122 160 196 207 219

where did you get yours ported and what did it run if you don't mind me asking? I'm doing gt40's (already have) on my 95 with ecam (already have) and explorer or cobra intake.

fastgtfairlane · Feb 5, 2009

just scored a set of gt40 irons on ebay for 360 shipped. im gonna get a valve job and port them out myself. ive been doing some research on where to remove the metal. they mostly just need a good cleanup and some bowl work. the exhaust ports will be ported and polished. im building a fresh 306 setup with a ported typhoon u/l with all the supporting bolt ons. its gonna be a while though for everything cause still gotta pay for the machine work. im shooting for 300 to the wheels. i think it will be attainable. still undecided on the cam however.

Mustang5L5 · Feb 7, 2009

I scored some P's today. This is the combo i want to put together

GT-40P's (untouched)
Cobra Intake (untouched)
65mm TB
TFS Stage 1 camshaft
24# injectors

Now, can i run 1.7's with the TFS and the P's?? Or am i limited to 1.6?

Also, what valve springs are you guys using? The Trick Flow ones??

http://store.summitracing.com/partdetail.asp?part=TFS-2500100&view=1&N=700+150+

Venom351R · Feb 7, 2009

tmoss said:
If you put your car up for any period this winter, port that stock lower intake for another nice hit in power. Instructions on how to do it yourself are on my website.

What is your site?

tmoss · Feb 7, 2009

that site came down but that article can now be found in the tech section here:

www'dot'eectuning'dot'org

Mustang5L5 · Mar 17, 2009

Is there a significant benefit to some "home" porting?

My car is laid up and i have the heads and my Cobra lower intake off the car. Anything I can do to improve either one slightly while they are off the car and I have time?

I was going to put them on untouched, but if there are gains to be had by some simple porting, I would like to do it.

thumper460 · Mar 17, 2009

You can make a bit more power by smoothing the bowls, then taking the Heads to a good performance machine shop and have a good street Performance valve job with a back cut on the valve. Of course there is MORE power to have them Ported !! But the above will pull more power and you can do most of it your self.. just be carefull!

Just me..................................

Thumper

99FiveOh · Mar 17, 2009

Some good info in this thread. I have an Explorer engine I'm working with, thinking about the Steeda 19 cam, any thoughts on that? 280 or so HP would be fine by me, anything more would be a bonus. I'm thinking about going with an S trim in the not too distant future, so I want to keep compression low.

XLR8TR · Apr 13, 2009

I've got the same setup as you do (GT-40P's, Cobra Intake, 65mm TB, TFS1 cam, 24lb injectors)
and I'm running 1.7rr's without any problems.

Official GT40P headed 300rwhp thread!!!

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