Unless your gonna port the 302's there a waste of time they flow the same as open chamber 318 heads and the compression bump you'll get will be about .5 on your CR which at best is a 2% power increase and from what I understand 318 factory gasket is pretty thin so if you go with an average gasket size you'll lose any gain.
Go with the 360 heads mill them down, the flow will offset the Compression check out the low compression 440 build on here.