4.6 need advise on flywheel different engines

On an externally balanced small-block Ford, both the flywheel/flexplate and the balancer must have the correct amount of imbalance for the particular crankshaft being used. Failure to use a flywheel/flexplate and balancer combination with the correct amount of external imbalance will result in serious engine damage.

That aside, I don't think they even have same bolts. The crank on one of them (I always lose track of which is which) has 6 larger bolts (10 mm) and the crank on the other has 8 smaller bolts (8 mm).

I put the bolt sizes in parentheses because I don't know if they are accurate.