I don't think there were any differences in the two...only possible problem is if one was from a stick and the other from a Dynaflow...I don't believe the Dynaflow crank had a boss for the pilot bushing, but I'm going on memory here...Also, your Special is pushing 4000 lbs. if not exceeding it with fluids in it.
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1953 Buick Special Riviera 45R
1965 Buick Skylark 44437 300-4V
1965 Ford Mustang
1965 Chevy Corvair Monza Convertible