GT40P.... worth Porting?

StangAlang0811

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Apr 24, 2009
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I have a set of GT40P heads, I have them sent out to get cleaned up and trued up... Im doing a pretty simple budget build. I'm trying to go for a good sounding, wheel torching hot rod. Granted a stock 5.0 are able to sound good and torch tires but Im lookin to step up... Im looking to get a Cobra or GT40 tubular intake to set on my heads. So if anyone wants to trade for a brand spankin new edelbrock RPM 2 intake with all bolts gaskets and a spacer, just let me know... My question is, with just upgrading to a cobra intake, 70mm th body, e303 cam or tfs stage 1 cam, bigger mass air, injectors ect ect... is it really worth my time and money to have the intake and P heads ported? for a daily driver will I notice the difference in power by stomping into it, with the occasional pass at the track. I got a 14.5 time right now with NOTHING done to it but exhaust, thats even with 2.73 gears... I need help, I wanna 12.9 second car. WHAT do I need to do to get it there, and is porting and polishing my combo a must to get it there?? BTW im not an idiot, Im very mechanically inclined. I understand gear ratios and what not. Just lookin for a solid combination to turn out a high 12 second car. THANKS for your time.
 
I honestly think you could get a 12.9 with ported stock heads pretty easily. A mild cleanup of the ports on the GT40P's, plus a decent cam (not the E cam, something dual pattern like the TFS1), and the GT40 based intake could get you in the 275 RWHP range and mid 12's with no problem. Grab some gears if funds allow. I'll hold off suggestions until I know if you're running an auto or manual car.
 
There are tons of guys running high to mid 12s on unported P heads. You just need a good hooking suspension to do it.


We have a guy on our local forum who's actually going high 12s on an untouched, unopened STOCK 302 long block. That's factory heads/intake/cam going 12s with no power adders. It's all in the suspension and the tune.
 
whats a good price on having those heads cleaned trued and ported? i'd like to run the 12's also. acutally a 10 sec car would be nice but thats completely out of my budget. hence the reason for the p's. i've heard the tfs1 cam on those heads and seems to be a popular match. sounds really good too.
 
The TFS1 is what most guys around here run with those heads and nobody bothers porting them. You need to upgrade the springs on them to handle the lift though. I can't say what it would cost to port them but i know new valves and a 3 angle job is gonna cost you around 400 give or take depending on the valves and the shop.
 
I honestly think you could get a 12.9 with ported stock heads pretty easily. A mild cleanup of the ports on the GT40P's, plus a decent cam (not the E cam, something dual pattern like the TFS1), and the GT40 based intake could get you in the 275 RWHP range and mid 12's with no problem. Grab some gears if funds allow. I'll hold off suggestions until I know if you're running an auto or manual car.

in that setup I bet the tfs stage 1 is maybe 5-10hp more than the e-cam, less torque obviously.

the e-cam isn't bad . . . it just only works well in limited situations.
 
whats a good price on having those heads cleaned trued and ported? i'd like to run the 12's also. acutally a 10 sec car would be nice but thats completely out of my budget. hence the reason for the p's. i've heard the tfs1 cam on those heads and seems to be a popular match. sounds really good too.


I sent my heads out to Manloves (thats what they call it in Delaware)(Fischer auto anywhere else). It costed me $48 for trueing them. $25 for cleaning, and $25 for magnaflux inspection. Im doing the valves myself and as you can see, looking into porting. I probably won't mess with it. But everyone telling me to get rid of the Edelbrock RPM 2. I dont wanna get rid of it, I'll probably just buy an intake. RPM 2 is too nice to sell. And you never get what you pay for them back.
 
I honestly think you could get a 12.9 with ported stock heads pretty easily. A mild cleanup of the ports on the GT40P's, plus a decent cam (not the E cam, something dual pattern like the TFS1), and the GT40 based intake could get you in the 275 RWHP range and mid 12's with no problem. Grab some gears if funds allow. I'll hold off suggestions until I know if you're running an auto or manual car.



BTW Im running a 5-speed car..
Im doing 73 or 76mm mass air
70mm throttle body
edelbrock RPM 2 (have - seen one on youtube same setup, runs pretty damn well)
24# injectors (have)
GT40 p heads (have)
MAC gt40P headers
FP regulator
190 fuel pump (have)
TFS Stage 1 cam
1.6 roller rockers
Trick Flow valve spring upgrade kit
Off road X-pipe (on car)
Mac catback (on car)

and unless im forgetting anything else, thats pretty much it. Those are my engine plans... I would imagine that being a 12 second car, but im not for sure. thats why im asking
 
The p heads aren't worth porting.
Figure their value is about $300, then a valve job, bowl cleanup, springs and milling are going to cost you $400 or so. Then add at least $250 for actual port work. That would put your total investend beyond aluminum heads. (doesn't matter if you got the heads for less, if you were to sell them, that's their value)

Shop well and you can get good aluminum heads used for $850 or so, which would make your car lighter and produce more power.

When it comes to p's, stick some springs on them and run what you have, investing any more money than that puts them in aluminum head territory.

12.9 is a nice goal, but that number has to do with alot more than just the engine. I'd be more inclined to pick out a mph goal when talking about gains from engine parts.

Also pick out a better meter, a 73 or 76 means you are going to use a C&L, and they are crap.
 
The TFS1 is what most guys around here run with those heads and nobody bothers porting them. You need to upgrade the springs on them to handle the lift though. I can't say what it would cost to port them but i know new valves and a 3 angle job is gonna cost you around 400 give or take depending on the valves and the shop.

I paid $550 for porting, slight milling, 3 angle valve job, new valve seals and magnafluxing. I paid $300 for the heads with Manley 1.94/1.54 SS Raceflow valves and upgraded 120 pound springs. My budget for the heads was around $800 and I have an almost race prepped set of heads for the money.

If you work it right and get lucky you can get a set of heads that will run with out of the box aluminum heads for less money. I would have just bought used aluminum heads but by the time I got them rebuilt (never installed a used head without rebuilding it first) I would have had more in them than a new set costs. And way over budget.
 
Hell i paid $450 for my valves/3angle/magnaflux/resurfacing. I should have gone ahead and milled them to 58cc but i wasn't sure what i would have for PTV clearance. That price is with getting a killer deal on some stainless valves that a guy ordered and backed out on buying.


My advice would be to spend the money you would spend on porting on suspension parts. If you already have suspension parts, start saving up for a nice set of used aluminum heads and enjoy the cheap power with the P's in the meantime.
 
For any reasonable amount of money, you can get P heads to flow 220-230cfm. That is right at the same amount as an Edelbrock Performer head. Pay attention to the cost - often times you can get a recently rebuilt Eddy or equivalent head for $600-$800 depending on what's been done. Then it's often worth shaving the weight.