how much more power would I get if I added some aluminum SCJ heads to my 1973 Lincoln block. It has been bored out 30 over and has an RV cam.
Holley street Avenger Carb. Eledebrock intake. iron exhaust manifolds.

Has a ton of power now just thinking a set of L&L headers and the aluminum heads would make some serious power?

 

becareful which heads you run, some of them have revised valve angles which require different pistons or valve reliefs.

it's a WAG to even try and guess how much increase, but honestly with a "RV" cam you might actually hurt your bottom end power with no increase on top end.

You also would need a different intake as the ports are different.

you would be much better off with a set of something like TFS street heads.