The 2, 3, 31/2, 33/4 and 4 Horsepower flathead Briggs motors all use the same flywheel diameter (but NOT flywheel!). This fact allows you to swap a 2015 Briggs push mower ignition coil onto say a 1972 Briggs 3 horse water pump motor with very little work! Briggs switched from points type ignition to electronic ignition (Magnetron) in about 1982, so any Magnetron from 1982 and up until 2015 when they stopped making the flathead engines, should fit onto the older engines that have the 2 bolt mount for the coil. Generally the 62XXX, 82XXX, 92XXX, 10P (4 horse), and model 110XXX 4 horse coils would all fit onto an older motor. As I mention in the video, these newer coils will fit and get the engine running again, however some of the newer coils have been redesigned for lower speed starting, exhaust emissions etc. I have tested them all out, and they seem to interchange fine.