Well, while it's true the slanty used that size clutch as mentioned,(I have the adapter plate/SB bellhousing & clutch assy/flywheel still bolted to a '76 tk unit I picked up),it'd
be a first to hear of a "late" bolt pattern on the crank switcheroo. I can't think of one logical reason Mopar would have to change production drilling of a crank that hadn't had
a change in 25 years for the last 2 or 3 years of production in this country, but that's never stopped mfr.'s from doing it in other areas, lol! I would pose this question on .org,
or see if SlantSixDan catches this thread, He has voluminous parts catalogs at His disposal. The service replacement #'s would call out any sudden change in interchange-
ability. Of course if the eng. is waiting & You've got the flywheels laying around...................You know the rest!!