Overheating 360 new engine

I wonder is the valves are adjustable? If too tight lash they open too soon and hot still burning gas will heat the headers cherry red. Raises the underhood temps ALOT.

What is your air cleaner system? Open to underhood air or sealed with a cold air pickup.

Piston ring gap too tight will put a lot of heat into the core when the gap ends butt.

My 65 B-Cuda with a 383 would over heat real bad. I tried different fans. Tried a bigger radiator.
The fix was a closed cop car aircleaner with two snorkels to pick up air from under the front valance.