Main shaft question

Does anyone know if the main shaft on on 36-64 is the same as a 68? I'm new to flatties and am tryin to run a big twin 4 speed with a belt drive and need to know if the taper is the same.

Taper is the same, however length is different. You need the correct length shaft to match up with whichever engine you are using. '64 and earlier, '65-'69, or 70 and later.

The transmission I have is a 65. Is that the same length then?

Also, thank you for your reply! It is greatly appreciated!