I am currently running two B-40's. One from the first run and the other from a later run. Both start and run great. The only thing I did was add one head shim. This seems to produce a little better break. I have a third one that will start the break-in process just as soon as I get retired, moved and get my shop set back up which should be by mid July. There are several other B-40's being used by some of my flying buddies and they are all good running engines.
One thing I have found about the B-40 is that you must follow the break-in instructions very closely.
Bill Hodges
43 days until retirement, but who's counting!!