302 heads

It sounds to me like the 302's will be fine for what you're planning on doing. Just get a clean set and try to avoid dumping a bunch of money into rebuilding them. I wouldn't cut them much either, as that will end up costing you a bunch with custom length pushrods and milling the intake.

The 302's came on 318's from '85-'89, if you can find a set in the junkyard you'll pay a lot less for them. I would just have them magnafluxed to be sure they're free of cracks, get a valve job and a quick surface cut just to true them up. Run them with a set of Mr Gasket 1121G head gaskets, they're .028" compressed, to bump the compression a little more.

If that's all you do to them, and you're not looking for anything much over 300 hp, the 302's will be great. Just don't be tempted to sink a bunch of money into them trying to make them performance heads, otherwise you'll spend more money than a new set of heads will cost.