Just before Brison took over, I believe A&M switched to using the Sachs crank. A&M originally only used a Sachs piston, & cylinder, on their own case. After Brison took over the cases were also changed. I talked to Gary about this when I got my first 3.2, and am pretty sure that is what he told me. It has been about 7 or 8 yearsago. Your motor could be an early Brison, or late A&M. I have several brown box ignitions that work fine. In fact the only bad, (inoperative) ignition I have is a newer silver box. Yours has the Bosch shielded cap already, so if it works, it should be fine. I have the mechanical spark on all my engines and would not care to change it out for the electronic advance. That's just me though.