I had an aircraft tug made by Clark with a Hercules flathead 6 that would not start in Minnesota cold no matter what we did. We used it to push dead cars around. I pulled the distributor and took it to a bone yard. The bottom of the Prestolite distributor that fit the head of the Hercules was exactly the same dimensions as a 4 cylinder Chevrolet Vega unit. I got that one and a even fire Buick 6 cylinder unit, swapped the 6 stuff for the four cylinder stuff, cut off the way too long shaft and pinned on the drive tang that fit the Hercules.
It has been starting every time all winter for over 30 years.
You might check on line for something that fits out of the box, HEI is available for Fords, Chryslers and who know what all these days, it is not expensive either, less than $100 in many cases.
