The only difference in the bellhousings between '53 and '54 is that in '54 Chev. went to side engine mounts and trans mount for 3 point mounting, in '53 they had mounts on front engine plate and on bell housing as well as rear transmission for a 5 point mount. I don't think either is better, only different. If you use a s'54 or later (up to '62) engine in a '53 or earlier you have to use the '53 bell housing to have the side mounts on the bell.
