There's another approach that eliminates the scarce and pricey stovebolt main bearings altogether. Using a set of good to fair condition original bearings, they're permanently attached to the block and main bearing caps with flat head brass machine screws, then the soft metal lining is line bored/honed to fit a set of main bearings for a small block Chevy 400 V8, leaving just the steel backing in place. Then the crankshaft is reground to fit the smaller diameter bearings. There are two advantages- - - - -the SBC 400 bearings are inexpensive and plentiful, and the crankshaft main bearing journals and block bore is the same front to rear. The original #3 bearing thrust flanges position the crankshaft in the correct front/rear location. As an added advantage, the smaller diameter mains also reduce turning effort on the crankshaft, lowering internal power loss.
Jerry
