There would be no reason to shim the bearing caps on a properly line-bored engine. The shims were a production gimmick to correct for less-than-properly machined bearing bores or slightly off-sized crankshaft journals. I like to bolt up the bearing shells in a block without the crankshaft installed, and measure the actual ID of the bearing, then subtract the shaft diameter from that reading to get an oil clearance figure. If a little more clearance is needed, I add a shim, but only on the engines with the dowel pins in the main bearing bores, to prevent the bearing from spinning. Newer-design blocks without the dowels definitely don't need to be shimmed, as it interferes with the proper crush fit of the bearing in the block. Those raised tabs on the bearings with the corresponding slots cut into the block and cap are called "anti-rotate" tabs, but with the right crush fit, they're not really necessary to prevent bearing movement.
Jerry
