Piston slap. Would that stop after it's warm? My friend suggested that but he can not hear any evidence of it when I take it to his shop.

I rebuilt the engine, for the second time after my cam went flat (no zinc in the oil, I now use EOS and Valvoline VR1), it didn't make the noise when I first built it.

The cylinders are .080 over, 307 pistons, new rings. It has a Crower cam and lifters. New cam bearings, Clevite, I think.
I did not `scope the fuel pump. I not familiar with that phrase