95Mustang5.0L

Hey guys anyone knows the difference between a Gt40 & Gt40p Heads? If I install Gt40p Heads on a 95 5.0, do I have to change the stock headers to sum aftermarket?

95Mustang5.0L

What is the difference between Gt40 & Gt40p Heads?

mattdel

P heads have a different spark plug angle requiring special headers. i believe there might also be a small difference in valve angle, but its negligable.

boonedj

yes and the p heads flow better and i have heard of guys getting away with using stock headers by flipping the plug wires i forget who all has done that but as we all know mjr46 will be able to tell you more about the dif.

J-n-R

Gt-40P heads have a revised spark plug location that requires a "P" specific header. They are known to be the best performing of the Iron GT-40 heads as cast.

I personally ran the original "L" head for almost 10 years. If I remember correclty I got one of the first 15 or so sets that hit Houston back in 1991.

Great head either way.

AdderMk2

seriously dude.... search

93 LX FiveO

IIRC, the stock 5.0L tubular headers will work on the "P" heads.

They are very similar really the only difference is the spark plug angle. The P's do make a little more power because of this.

lehrskee

i also was wondeering about these. they come equipped on the 5.0 explorers right? so if i were to buy the gt40p heads i wouldnt have to change anything? i read that you might have to tune it accordingly... but besides that its just a swap out?

FivePointOhh

you'll lose compression with the P heads so its a good idea to get them decked down .030 to get those CC's down unless you're going boosted.

PRO50SC

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Thanks and welcome to MF!