gt-40p vs gt-40

[MarcMonteverde]

i was woundering what the differance was?
my buddy is gonna sell me a set of gt-40p heads
for 400 but i heard the gt-40s are better
oh they are cast iron
how much horsepower gain can i expect to see if any
also am i gonna need to mod anything
thanks!

 

[hollywoodstang]

i was woundering what the differance was?
my buddy is gonna sell me a set of gt-40p heads
for 400 but i heard the gt-40s are better
oh they are cast iron
how much horsepower gain can i expect to see if any
also am i gonna need to mod anything
thanks!

In your sig you already have gt40 heads... They are basically samething. gt40p is the newer version ford produced. gt40p require special headers. gt40 do not. if you already have gt40 heads i would just keep that instead of "P" heads.

 

[NIKwoaC]

P heads have the spark plug relocated closer to the center of the combustion chamber, that is why they use different headers. As far as flow characteristics, I can't say which does better over the other, but I figure others will speak up on that. From what I remember, its up to debate, but the P head was supposed to be an improvement...

 

[JKidd]

P heads have the spark plug relocated closer to the center of the combustion chamber, that is why they use different headers. As far as flow characteristics, I can't say which does better over the other, but I figure others will speak up on that. From what I remember, its up to debate, but the P head was supposed to be an improvement...

Pretty much what I have read as well. The P's are supposed to flow a bit better than the regular GT40s (and not by a whole lot) and do require different headers.

If you already have GT40s on the car, don't spend the $400 on the P's. I do not believe they are THAT much of an improvement over the regulars. Plus you will have to invest in new headers. If you want $400 worth of performance improvement, pull the heads and lower intake and have them ported and polished. THAT will give you a very nice improvement.

 

[SVT32VDOHC]

Agreed. Not worth changing them out.

 

[Maryland Stang]

I have a question about this header issue.

From what I've read the stock Ford Mustang headers will work with the Ps correct? If the stock headers work and the P headers work then wouldn't it be safe to say that it's the regular GT-40s that need special headers?

Or that none of them need "special headers", just different ones?

 

[stykthyn]

but you can use regular headers on the p's, but you will never get a spark plug wrench in there without taking the headers off first

 

[MarcMonteverde]

kool thanks! yeah thats my old stang it was stolen i had alot of work done to it
someone got a nice stang but im building a new one thats why i asked
i should really change that tonight haha
thanks for all the input\