9 1/4 in an a-body?

Sweeet. Then, you'll need spring pads since the ones on the rear are for a different spring. The ISO springs have a large hole to locate the spring where the older rears do not, there spring locator hole is small.

Gear ratio is limited. I see mostly ratios up to 4.56.

The axles are tappered. I do not know if theres support in the aftermarket for this rear or what can and can not be done for them.