what is the difference from the gt40 and gt40p heads?

 

Somebody correct me if I'm wrong - but I believe the GT40P heads require intake and exhaust components specific to that head, while GT40's share the same intake / exhaust configuration with everything else under the sun.

I hear they flow better than the average stock head though.

 

A standard GT-40 was introduced on the 93 cobra and is a decent little head for a mild bolt on application.
The GT-40P are basically the same head but with an angled plug design. They are a pain in the @#$ because of that issue. They are V8 ford explorer heads.

 

GT40 heads have 1.84/1.54" valves and larger ports for about 20% better flow than E7TEs, but otherwise look and fit the same as stock heads. GTP heads have 1.84/1.46" valves but have better port designs that flow about 10% better than GT40s, but they also have a radical spark plug angle that makes fitting headers a problem.

 

so where would you buy headers for the gt40p. i just bought a 351 for my 89 f150 and planned on improving the heads a little so i figured the gt heads were the way to go

 

Simply avoid GTP heads if you can, but if you did end up with a set standard longtubes or unequal length shorties will work with a little customization... i.e: a few header tubes may need to be clearanced for the plugs.

 

so what would you do to the head try to find a gt40 or just use stock

 

I'd keep the stock heads until I could find a deal on a pair of aluminum heads. I see them on cl for ~$500 all the time.

 

Yes.. this is exactly why it's not worth spending any more than a few hundred dollars on stock heads, because even the worst of the aftermarket heads have more performance potential than GT40s.