[dragracerray]

I assume your starter bearings and starter drive are healthy. I remember a BBC block my brother and I had that did the same thing. We machined the mating surface of the starter. Not sure it solved the problem but it was much better. Don't remember how much we removed but if you go to far you can always shim back. Maybe try it with a nosepiece you don't care about (ie not a cast iron nosepiece). If you find this is the problem machine the block next time it is out so you can use any unmachined starter. Can you use a start retard device? Good luck, Ray