596 casting or 308 casting for mild 360 4bbl

How's the block under the 308s? Both are open chamber heads, 308s are stronger on the exhaust and I think the 596s have better intake flow by a touch- very little difference between them. If you're talking about 302s- forget them completely, 318 trash heads. The bigger perk with 308s is that they're already in proper order for running a roller cam on a roller block, that's worth far more than the slight gains on the exhaust side. So if that's not a concern/consideration- I'd forget them.