What would be the best cam to work with GT40p heads? When installing these heads do my stock headers bolt up? Is there anything else I would have to modify to replace my stock heads with the gt40p heads?
Yes... I recommend MAC GT40P specific shorties, if shorty headers is what your after... If you want LT's, then the MAC Tru-fit longtubes fit real nice... at least in my case... Also, I would look into the Crane 2031, Trickflow Stage 1, or Steeda #19... mainly because our cars are picky when it comes to cams... For the best performance, call Buddy Rawls or Ed, and have him grind you a custom cam... Also, upgrade the valve springs before you install a cam, because the stock explorer springs won't cut the mustard...
The stock HO cam can be a very good match to the P heads. When you look at what the P heads flow, they flow about 4cfm more at .500" than they do at .400", so the .444" lift of the stock cam is a great match. The stock cams vary quit a bit in duration (204~212°), so I suggest when you do the heads that you get a degree wheel/magnetic base dial indicator and see exactly what your cam events and duration and lift are. I have the early 87 "high ramp rate" cam in my 2/88 built car and my cam came out to be 219°I, 212.5°E duration @ .050" lift and the lifts were .448"I, .436"E. Turns out the duration and valve events are VERY close to the Crower 15510 cam and when I asked a well known custom cam supplier how to install it, he recommended a 109° ICL.