Heck, not much to it, so I didn't take a before, there will of course be an after picture show on my engine build. The area on the snout of the B21 crank that is the bearing seal needs to be machined off and a keyway cut to accept the timing gear for the B20. The rest is the same (ish). By the way, there are some discrepancies in the bearing sizes. They are close, but the B20 is slightly larger (0.004"). So the crank works, but has to be set up with B21 bearings. I'm not sure why the bearing sets are all listed as B20/B21/B23, 4 thou is something. All of my dimensions come from the factory specs - but it can be made to work.

I'll have the crank back in a week or two.