There are basically two versions of connecting rods used in the big block Chrysler. "B" (low deck) blocks used a 6.358" version, for which there was only one casting number, 1737692. "RB" (raised deck) engines used a longer 6.768" rod, of which there were several different versions available, with different strengths and casting #'s. All stock production big block wedge rods use the same bearing and pin size, along with 3/8" rod bolts.