I've already done the same swap in the 78, so the work load is well understood. (not that bad to tell you the truth though, just don't try keeping so many bits and pieces of the original electronics and harness.)

I forgot to mention that the B230F has zero miles since rebuild, just dyno break in.

The original B21F seems to be in fine condition (true milage unknown). I don't really know much about the fuel economy with these engines (this is the first good one I've owned).