high,

Try 2 more tests.

1) are they the same diameter? If not, they will only fit under the coils if they are on the correct engines.

2) are the key slots in the same position? I don't know if manufacturers have a standard key position or not, but if the key slot is not at the same position on the shaft when the piston is at TDC, you might be able to extrapolate which flywheel is which by comparing the key position relative to the magnets.

Good luck! BTW - I assume the shaft tapers are the same ... that would be too easy.

Bedford