"Does anyone know of a year and model that is a fit without having to buy and swap out the pully."
37 GC,
Here's what worked on my '52 Ford 8N tractor that retains the original 6 volt starter.
1. A 1970 Toyota alternator with the original 5/8" pulley. 2. A 1960-69 Mopar voltage regulator (Wells VR 706, Standard VR-101, Niehoff AL-169).
These 2 transplanted items have worked perfectly together for about 20 years requiring only machining a simple aluminum alternator mount that attaches to the original Ford generator mount and mounting the Mopar voltage regulator on the back side of the dash. It probably sounds too simple to be true but it works.
I still have the wiring diagram if you don't mind the simple, inexpensive approach.
Another option you have is a James Peterson voltage regulator that fits inside your '37 generator. I have one of those in my original '36 Chevy PU generator and it works great!
