New motor, loose rocker...

Cut your oil filter open, see if there is a bunch of extra Black Residue in there from the cam wear, even look for steel in there too. Take a magnet to the paper part of the filter after you cut the tin off the filter, this will easily pick up any steel that is coming through your oiling system and getting caught in the paper element.

Lot easier to change the oil filter, than it is to change a cam and lifters and find out they are good.