Even worse, who knows if any of the current rotating parts are correct for each other.
Lots of ways to mess this up. When I bought my "70" Barracuda it had a "70" external balance flywheel.
P.O. probably thought "70" body, "70" flywheel, what could go wrong? Plenty. It also had a "67" engine
and the correct for that engine internal balance damper.

In theory, there is no difference between theory and practice. In practice, there is.