OK, I just went through a bunch of parts books, and found the numbers for the crank for a variety of years and models. What I found is that 203655 replaces 302530 for any year, without regard to seals or bearings, etc. As always, that doesn’t mean that 302530 will always replace 203655 (backwards compatibility). Note that 302530 kept showing up as late as 1957 (but superseded by 203655).
Conclusion: Now I have to dig back into my brain’s memory bank. I remember that somewhere along the line, the lower seal area started being chrome plated so the carbon seal wouldn’t rust to the shaft and fail to move up and down as the crank moved up and down within it’s end play limits. I think that probably is the difference between 302530 and 203655. Could be mistaken.
Whew!!
