Hey guys this weekend i was helping my friend put togather the low end of his engine, and when we torque the caps onto the connecting rods the engine isn't rotating smoothly. He is working on a budget, and sent out is rods and pistons to a machine shop to have them assemble, and he didn't stamp tham, and now we think the machine shop switch the caps with the different pistons. Is there any way we can figure out which cap goes with which piston? Any suggestions would really help.