New heads

I have a set of brand new Edelbrocks sitting on my desk right now. I could throw them on my 318 without doing anything, but I would have several headaches to deal with: loose casing flash that could cause issues with the oiling, a raised helicoil that would cause an exhaust leak. I need to check the valve guides for proper clearance too, but its nothing that can't be overcome with a little care... point is, these heads are REALLY cheap for their volume compared to factory stuff that has to pass an oem warranty, so you are going to have to deal with the quality issues no matter what. Edelbrocks, Speedmaster, Trickflow, etc. has to pass on some of these issues to us for them to be remotely affordable.
Buy a set of aluminum heads, but expect that you need to check things out. If you have no experience with engines, you can still catch a lot of the issues like flash, things that would cause a leak etc. Even the valve guides, you would likely notice a valve that is way too tight and would stick just by feeling.