The diameter of the flywheel changed when Chevy went to 12 Volt. Why? I have no idea. When they changed the diameter they changed the tooth count and the pitch. On the starter they changed the pitch of the teeth, and kept the tooth count the same. Why? I still don't know. So in short, if you have a 6 Volt flywheel, you need a 6 volt starter. It will work just fine with a 12 Volt system. If you have a 12 Volt flywheel, you need a 12 Volt starter. It will not work with a 6 Volt system. But there is some good news, they will interchange, and fit on 216 and 235 engines. They will fit inside the old and new bell housings. So if you have an AD truck and you put in a later 235 use the old bell housing and flywheel and you are good to go. The bell housing was changed on the TF trucks. I think that was to fit the new at the time V8. The cross member was changed for the same reason. Since the TF were 12 Volt it was simple I think to make the diameter the same as the fly wheel as the V8 and save messing around with different starters? Best I got any way. By the way, the ring gear is specific to the flywheel. You need the small diameter ring on the small diameter flywheel. Any one find an error in this?
