Difference between 8ba and 59ab flywheel

[Bruce Lancaster]

Ol Ron's book gives a dimensional method of sorting them...essentially measuring distance from flange on one side to friction surface on the other. I've always had the right sort lying around so never worried about it.
I believe there is some offset, fractional, to ring gear. Actual interference problems I have heard of involve early wheel on late motor, the opposite of what you are wanting to do.
I don't see why the different width of the gear would matter.
Empirical approach...bolt it on and see if engine can be rotated. Add starter and see if it engages and disengages when fed electricity. I think the late ring gear will be slightly forward of early gear proper position.