I think the only way you can tell what it's for is to compare it to another with a known origin. The flywheels with the drilled external balance holes are easier to ID than the ones with the scallop cuts.

The heaviest external balance is the LA 360, next down is the cast crank BB but, since the cast crank BB's didn't generally get stick shifts, there's a good chance that flywheel is from a LA360.