I believe what Jerry said about Quest and the MPC assets. The guy I know that worked at FSI towards the end said they had recieved a lot of balsa in MPC boxes. I know that Larry had gotten to know Bill pretty good from their business dealings on motors. This is speculation but Larry probably worked out some trade for motors he was making for Quest.
The dangers of making BP motors are VERY real!!! I remember back in the pre historic days (1970's), I remember Lonnie telling me that Gary R. and Scott D. thought we were nuts for our BP motors. Of course we thought they were nuts with some of the motors they were making. Making BP motors , it can go bad real quick. Watching out for any static sparks, keeping humidity right, not paying attention to your press and tooling. It doesn't take much. The only fire/explosion(and it was not really a expolsion it was a over pressurizing of a structure) was when a guy got a hot bit into a F100-xx. I did see the aftermath of Lonnie hand loading a 21mm motor when mandril hit the spindle and shot it out of his hand. You dont pay attention and get careless it can go bad real fast.
Myke Bregenski (I think we all butcher his name) real nice guy. I met him couple times. About ten years back he was selling some of his motor making books on ebay and I just missed them. Myke always caught flack for his engine ratings( F23.48273-xx ). Had a Physics professor that would ride our a$$ about carrying a answer out to too many places. All the testing equipment I ever saw back then was not hyper accurate. I doubt those tolarences in the tenths could be held.