Thanks tjs44. I figured to cut the crank. I was curious about how the block # was the same for the 421 S.D. , and kind of guessed they had used the same block but bored the mains larger. Can we pass that off as a freezer manhattan question? Are these chinese cranks as bad as they say? I,m not opposed to a 4.25 stroke, cast, low RPM engine for dad, as long as it would hold up. Torque is good. One more question, Are the rods the same for a 421 As a 389?