Terry,
302 heads are out there and sould be in most junk yards, and will work the best on a 318 but if a 349 engine is what your after then the 360 1.88/1.60 valve heads will work better
If the 302 heads were gone over and the 1.88 and 1.60 valves were installed would they still work well on a 349? I already have a set of 302s that came on my donor engine and I like the idea of closed chambers.