Early History Questions on Flathead Football Helmet Style Distributors

[rhpope]

Was there a particular application for the mechanical advance limits for the 40B (16 deg. of advance @ 2500 rpm) vs. the 11a (24 deg. of advance @ 2500 rpm)? Was the 40B the very first one, say in 32-up a few years and then switched to 11a in the later 1930's. Also, was this at all related to the 2 bolt vs. 3 bolt coils?


As referenced in Bubba ad for the early distributors:

https://www.fordbarn.com/forum/showth...108#post767108

Thanks,
Roger