I built a 355 shortblock for my camaro about 3 years ago. I am now going to finish building it after years of saving for more parts. I dont remember if I ever set the thrust on the main bearing after installing the crank...I did on preassembly. Is there a way I can check this with the rods , pistons ,crank , cam, and harmonic balancer installed. Can I just loosen the main cap and give it a couple of whacks with a rubber mallot or do I have to remove the rods , cam , harmonic balancer etc... thanks

 

You could probably do it by using two feeler gages, one on each side of the bearing at the same time, and adding up the readings.

 

thanks..do you think I need to loosen the main caps and whack the crank with a mallot to make sure the bearings are in line?

 

Won't need to that if you measure on both sides of the same half of the bearing.

 

The whacking that You're talking about is called seating the thrust. It's kinda old school but effective. Like Pete said, You need to check Your clearances. The right way is with micrometers, but use feeler gauges at least.