On mine the pocket ID was too small to fit the nose of an original Nippondenso mini starter. Had it machined larger and all was well
I had a feeling this was the issue. I really don't want to take this whole transmission out again.
How much was machined off in the pocket?
I'd be surprised if it was .020". I just remember thinking "are you f'ing kidding me"? Before pulling the trans off the engine. I was not impressed with the ultra-bell at all.
Maybe a cartridge roll on a die grinder would open it up enough.
I was using it to run a 518 in my car- just a heads up- you need a 10" converter to fit in the bell
