First thing you need to do is to determine what voltage your current starter is. The easiest way I found is to take a close look at the bendix end of the starter.....both 6 and 12 v have 9 teeth on the bendix gear, but the 12 volt starter has an armature shaft diameter that about 1/2" in diameter and the outer diameter of the bendix drive gear is about 1". On a 6 v starter, the armature shaft is closer to 5/8" in diameter and the bendix gear outer diameter is about 1-1/8". The 12v flywheel has 168 teeth and the 6 v 139 teeth. You must use a 6v starter on a 139 tooth flywheel and a 12v starter on a 168 tooth flywheel. You can run a 6 v footstomp starter on 12 v as long as it's on a 139 tooth flywheel. It's a common practice. However, you can't run a 12v starter on a 139 tooth flywheel. Obviously, you can't just swap bendix drives because of the difference in armature shaft diameters.
I'd suggest you pull your starter and check the bendix drive gear and even count your flywheel teeth if you have any doubts about whether you currently have a 6v car starter with a 12 v solenoid running on a 139 tooth flywheel or a 12 v solenoid controlled starter running on a 168 tooth flywheel. Removing the sheetmetal dust cover on the lower section of the bellhousing (4 1/4-20 bolts) will give you easy access to the flywheel.
12 v footstomp starters are scarce and I wound up with one pieced together from an auto electrical shop. The 12v solenoid controlled starters are available from local flaps (NAPA) and unlike the foot-stomp I had built, are reasonably priced.
Hope this helps.
Dave
