What is the difference between the GT40 and GT40P heads? I've read that the GT40P heads require different headers or exhaust manifolds than the rest of the cylinder heads, what's the difference with them? In my quest for more performance for my 90 Bronco with 302FI I'm looking at other heads for it. Before I go to the salvage yard I need to know what I'm looking for. I'd like to go with the Ford or Edelbrock aluminum heads but they may be out of my budget so I was looking at the Ford GT40 cast heads. I have the E7TE heads on it now with some porting, should I just stay with them and increase the valve size from the 1.78" intake/1.46" exhaust up to 1.84"/1.54" or just look for something better?

 

Engine Forum might get you a quicker answer. What I do know is that the OEM 302 heads are circa 1960-something technology so ANY improvement in flow through the heads should yield some marked improvement in performance. Beyond that, I yield to anyone with a greater knowledge of the aftermarket parts.