9 1/4 rear end?

Fitment into an A body is an issue since they did not put that rear into anything small. Late year B bodies got them. Cordoba's Magnum's etc... And trucks. There used today in the big Rams. LA and HEMI engines.

There's also axle replacement in shortening the rear issues. Are you going there?

While a bigger ring gear is stronger, some idiots here will point out that it is a C clip rear. For some this is a problem. There worried about failure. Rare under low power cars.

Not always a sure grip ethier