I had to revise my posts here because I couldn't understand what was going on with this situation. After looking at photos of other Tecumseh engines it was clear this crank wasn't the same P/N as what I'd been seeing. Without a shoulder, the shaft bearing/bushing gets squashed against the crank by the spacer included in the TC kit. Additionally, the spacer didn't provide for proper alignment of drive & driven pulleys. The collar I made solved both problems.
Anyway, sounds like I'm talking to myself on this so I'll file this one.