Rear end selection help and opinions

For 3-400 hp I imagine the 8 3/4 will be more than up to the task.

If you put out the feelers you can get an unmolested A-body 8 3/4 SBP complete (drum to drum)in the sub 1000 range, with a limited slip center section I would expect to pay a few hundred more.

Keep on mind I'm talking used, so some rebuilding might be needed.

Your target gear ratio is good compromise for hwy and strip (others have more info there)

Just my two cents