Another way to align the alternator would be to use a spacer behind the pulley of the alternator. A flat washer, the type used on a multi-fit mag wheel that uses a wheel nut with the type of threads that go down into the wheel hole, works perfectly. My wheels use a 7/16" wheel nut with a shoulder that the washer butts up against. It's thick and the I.D. is almost exactly the O.D. of the gm shaft. I used one on my 261 to line up the alternator when I did a conversion from the gennie.
