New 318 build, just need some input.

I think you will be alright with piston to valve clearance, the valve releifs are pretty big on the KBs but check it out anyway. (Clay is cheap)
Mine are 0.015" above deck and had heaps of clearance with a 0.574" lift cam.
The 302s aren't the best head but if you have a fresh set already clean the bowls up and any casting flash in the ports and send it.