318 low budget heads change

You'd be best off with the 302 castings on a 318. The 360 heads on a 318 drop compression and don't offer much added flow that the 318 can take advantage of. The J heads are nice for the big valves and such, but again, you wouldn't see a big advantage with the 318. The heart combustion chambers on the 302 castings are the way to go for a 318.