rod and main bearing ?s

This is caused by a out of round crank journal,and the firing order on the crank.If you have the crank turned,and allow for a clearance of .0025-.003 on the mains and the rods you will elimanate 95% of the problem.The clearance can be checked with micrometers and a plastic guage.If not in spec,return the crank and have a .0005-.0010 remove with a polishing strap to get the right clearance,mrmopartech