GT40 vs GT40P?

[duststang]

I was wondering if someone could explain the difference between GT40 heads and GT40P heads? which are better?

[Pitbull1052]

I've been told they non P's are better only because they use the same headers as you'd use on any other 5.0 motor. I think the plugs are at a different angle is why. I don't know from personal experience though.

[Steves LX]

Here's a flow chart for SBF heads. http://www.carbdford.com/tech/headflow.htm

[duststang]

GT40P flow better than the GT40 even though the GT40 has bigger exhaust valve. Im I reading this right? Is there a difference in the headers needed?

[duststang]

thanks i think im gonna get P's

[Pitbull1052]

I'm 99.999% sure you'll need different headers

[Pitbull1052]

I'm looking at doing the same swap but will prolly go with the non P's since I already have headers on the car now

[stang5slow]

so what ones to go with if you already have aftermarket headers? i have 1 5/8 shorties

[duststang]

found this info on net?

GT40P Headers: These are all P specific or confirmed fit:
Ford Racing- M-9430-P50(Stainless) & P51(Ceramic).fox

Mac: P/N 50158 1/58" ceramic shorty (fox)
54158 301.50 (SN95)
(From MAC website)

All MAC and BBK longtube headers for both fox and SN cars work if you use 90* plug ends and cut down a plug socket for access.

Un-confirmed:

[plated]

just about any longtubes wil lwork with p's iwent from gt40 to the gt40p's and the p's were a much better head go wit p's

[Marker1989]

FYI I have P heads, Mac longtubes, and normal ford racing plug wires (not 90 degrees).. not a problem, none of the wires are too close to the headers and there is only ONE spark plug (#4) that is difficult to change without a cut down socket. Everybody makes a big deal about the complications with these heads and all I can say is what complications.

[duststang]

Thanks for the info is very helpful!

[clueless_racing]

I just bought a set of p heads for my setup and i also had been wondering about the header fitment issues.this info helped alot.thanks guys

[Steves LX]

I will tell you from experience that BBK 1 5/8 LT's are an absolute pain in the ass. You must use 90 degree boots and good luck getting to plug 6 and 7 without a cut down socket. I have a friend(12SECLX) that runs 40p's and he uses BBK 1 3/4 LT's and he has no problems at all. My wifes motor has 40 P's as well and I bought the Ford Racing P specific shorties for her's and they are wonderful.