340 steel crankshaft

Back to 340 crankshafts.
I am putting together a 1972 340 (cast crank) engine and have a few steel cranks.
Two from 318 poly engines and one from a 1966 318.
My other oddball 'steel crank' is from a 1968 340 and it doesn't fit in the 1972 block?
The crank bearing flanges hit on the bearing supports.
I took it out of a 1968 340 block to fit a stroker kit so I really bemused by this???