[TK in LA]

Hi guys. Here is my problem. I have a B motor that was rebuilt a long time ago and had insert bearings installed on both the rods and into the main bearings. I'm in the process of rebuilding do to a water leak in the front of the block casting. That part has been fixed and I re-sleeved the block back to standard and it has a fresh valve job on a hardened seat set of Chevy (?) valves with adj. lifters. Here in lies the problem: the mains and rods were both shimmed even though they are inserted. The crank is close but to far out to remove the shims. I'm going to grind the crank to the correct clearances but I'm having difficulty finding the correct bearings. The rods are old AER bearings and I have a question in to them if they are still the same as there latest design. The problem is the mains. Other than a small G in a circle. there is a P/N of C3J C . I have no idea who's bearing they are or what they fit to replace them. They used two sets of bearings on the rear main and the center. Any ideas? Pictures show the markings.