Just sold a guy an engine for his beetle. Its out of a 66 T3 so it's 6V. He's converting it to upright, but needs to put on his 12V flywheel. I can't remember if it's a direct flywheel swap or not. His flywheel should have an o-ring in it, and I know the 6V one didn't. Isn't the 6V crank ground differently on the end? I can't remember for the life of me, so if someone could shed some light on this, it would be great.