gt40 heads Vs. gt40P heads - Ford Mustang Forums
 
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post #1 of 8 (permalink) Old 04-29-2012 Thread Starter
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gt40 heads Vs. gt40P heads

i was looking to upgrade the heads on my 91 mustang while saving a bit of money, and some of the guys on here recommended gt40 heads off an explorer, however i have found that there are 2 different kinds (the gt40 and the gt40P)

so i was wondering if someone could tell me the differences and which one would maybe be better, thanks!
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post #2 of 8 (permalink) Old 04-29-2012
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gt40p heads have the exact same intake and exhaust cc that stock heads do...BUT, the combustion chamber is angled differently and creates more compression than stock or gt40s. Honestly, I would take either or depending on the price, they are about the same hp gain wise. The gt40p heads have different angled spark plugs that make the sn95 stock headers useless though... Not sure if this is the case with a fox.

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post #3 of 8 (permalink) Old 04-29-2012
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Originally Posted by johnGT View Post
gt40p heads have the exact same intake and exhaust cc that stock heads do...BUT, the combustion chamber is angled differently and creates more compression than stock or gt40s. Honestly, I would take either or depending on the price, they are about the same hp gain wise. The gt40p heads have different angled spark plugs that make the sn95 stock headers useless though... Not sure if this is the case with a fox.
Yes similar header problems on a fox. I think it can be circumvented with some imaginitive wiring and plug boots.
OP, read this Five.Oh Info : The Ultimate Ford GT40 and GT40P Cylinder Head FAQ
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post #4 of 8 (permalink) Old 04-29-2012
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All the information you need (and should research) can be found right here:

Five.Oh Info : The Ultimate Ford GT40 and GT40P Cylinder Head FAQ

'94 Laser red 'vert. Still a 5-oh... for now
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post #5 of 8 (permalink) Old 04-29-2012
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Wow, great minds really do think alike

'94 Laser red 'vert. Still a 5-oh... for now
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post #6 of 8 (permalink) Old 04-30-2012
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first hand experience with this,among other things. gt40 heads have bigger valves, but the gt40-p makes more power. the gt40 head can be ported,
whereas the p heads only a slight massaging and bowl work will do wonders. If you try to port these you will probably lose velocity and hurt your performance instead.
the gt40 heads will work with any stock exhuast, or regular 5.0 headers.
the p heads on the other hand you will need to use either the frpp offerings, 90 lincoln stock tubular headers"lincoln logs" or bbk 1515 headersin order to fit. you will also need some 90 deg spark plug boots and some heat socks as well.
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post #7 of 8 (permalink) Old 04-30-2012
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You can look here.....

Five.Oh Info : The Ultimate Ford GT40 and GT40P Cylinder Head FAQ

2014 V6 Deep Impact Blue Mustang, Borla Type S, 2.73 (Uughh need 3.73)
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post #8 of 8 (permalink) Old 04-30-2012 Thread Starter
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you guys are life savers! thanks!
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