Just a FYI on heads, I've used 360 heads on 318's more than once. I've had them milled about .040, cost about 60 bucks for the pair. And NO, I did NOT do anything with the push rods or intake, bolted everything together as normal. Worked fine ever time. Many here will NOT agree with what I wrote here, and that's fine, but I will take flow ANY day of the week and twice on Sunday over compression. Both will help, but when I have to make the choice, give me flow and I'll dust the rest :D !!!