c4king

hello fellas, im looking at buying a set of brand new gt40p heads for this 302 build im doing.
my ? is i see there is two diffrent types, gt40p,&,gt40 whats the diff? also i have herd that the 40P head use a diffrent header? what headers will work on the p-head..
thanks for any advise and help.. also do you by chance know the port size on these heads?

mjr46

basically either gt-40 head in it's stock unported form..it would be a waste to have a cam with a much larger lift than .500 as peak flow is reached on those heads about there..of course for those who have a custom designed cam you could increase duration and stuff more air in that way..but either way most ots cams you may choose .500 would be the limit..as for the diff in the gt-40p heads vs gt-40's is the way the spark plugs are installed which on the p's require a special header..some claim a bbk header will work with the right choice of angled wire ends..gt-40's came with 1.84/ 1.54 valves and were on 93-95 mustang cobra's..early style ford lightening's and up to 97.5 explorers equipped with the 5.0

c4king

o, ok so i would be shooting my self in the foot with the ford f-cam that i plan to run then.

mjr46

no not really.. the f-cam should work okay...I have one in my 92 with stock e7te ported heads..and it runs okay

FLcracker9

There are a couple of other differences between the twoheads. The P heads have smaller combustion chambers for a little morecompression, they have smaller valves, but they flow better than the GT40s because of the "turbo swirl" combustion chamber design. Either head will be an improvement over stock. The P head performs betterin stock form, but will require different headers, or in some cases, regular headers can be used with90 degree boots on a couple of plugs. The GT40 heads area more popular choice for porting/modifying.

c4king

will i have to upgrade the springs on the heads? to like a dual spring?

c4king

also im putting this 302 in a 96 mustang and going carburated what intake would you guy use?

red95gtconvert

Weiand stealth.

SeePonyGo

I'm running the GT40-P's with a Trick Flow Stage 1 cam, 1.7rr, and MAC longtube headers with no problems.