Would I end up with the same results if I port my Cobra heads vs porting heads off of a GT? I'm pretty sure the Cobra heads have bigger valves, but not possitive. And if you know the valve sizes, that would be nice.
The GT heads are E7, whereas the Cobras have GT40s. The E7s came with smaller valves and were just not as stout of performers as the GT40s (by design). If your going to wort heads, and have both, port the GT40s!
Cobra heads have 1.84 intake and 1.54 exhaust, and stock none ported they flow 196cfm @ .600 lift.
if by GT40's your referring to the GT40P heads (assuming), which come from the explorer, they have 1.84intake and 1.46 ehaust valves. They flow 193 @ .600 lift....All this is off a Ford website, i wrote it all down a couple months ago...Welp, there you go. Those are both stock, non-ported heads
Welp, damn, i feel stupid, you were talking about stock GT E7's...ok, i need to start reading slower. Welp, E7's have 1.78 intake and 1.46 exhaust and flow 164.6 @ .500 lift. I hope some of that helped you. Goodluck!