heads, how much hp gain??

[Unit 5302]

Stock heads = 155cfm
GT-40P heads = 190cfm
Most aftermarket aluminum heads (Holley, Edelbrock, etc)= 220-230cfm
TFS and AFR 165 = 250cfm
Race heads = 260-280cfm

Stock intake = 135cfm
Explorer intake = 190cfm
Cobra/GT40 intake = 200cfm

The big flow aftermarket aluminum heads won't give you any hp over the GT40P heads if you don't have the rest of the setup to use them.

Quickest people running GT40P's? I think the Trophy Stock guys are down into the 11's pretty good, trapping over 110mph on them. Ford crate engines are rated at 320hp with them, and most people get an additional 20-30hp more than that with more aggressive aluminum headed combos. It's all up to you, but for a street car on a budget, the GT40Ps look damn good to me.