Are you positive the coil is bad? Those 1930s Johnson coils were pretty bulletproof. Often, it's the condenser that is the culprit, or points in need of cleaning/polishing/gapping at .020". That said, watch eBay, maybe place a free ad on the AOMCI.org site's boards. They're not something you can get new, so any coil you find is going to be used or new-very-old-stock. Some folks with the time, knowledge and means have re-wound old coils, too.
