Need help w/ my 85 302...cam? GT40 heads?

Ok guys. My 68 cougar has had a mystery 302 in it since I've owned it (5 years). It finally started to pull coolant into the cylinder (bad intake gaskets), so I got a used RPM intake to put on there. I pulled the old intake and I have spider and dog bones (that means its a roller cam right?). So I got a mirror and looked to see what heads were on there. Sure enough, they are the E5AE heads. So, before I was basically waiting for this thing to blow so I could put in a built motor. About a year ago I picked up some 97 explorer GT-40 heads for a future build. Now I'm thinking I should go ahead and put the GT-40 heads on while I have the intake off. I already have shorty headers.

What am I looking at compression wise w/ the 97 GT-40 heads (bigger chambers than 93 cobra heads) and the stock 85 pistons (assuming that is whats in there)?

What am I looking at HP wise (I know its a guess) w/ the big chamber GT-40 heads, RPM intake, stock 85 cam, holley 600 and shorty headers.

thanks
Austin

The 96 and early 97 5.0 explorer had real GT40 heads w/ 66cc chambers. Mid year 97 ford switched to the GT40P.

I've been doing some research and from what I have found, my E5AE heads had about a 66cc chamber as well. So at least I won't loose any compression doing the swap.