8 1/4 rear end questions

My Scamp currently has a 7 1/4, 904 tranny with the big bolt pattern. Originally I considered an 8 3/4 rear end but I'm not keen on sourcing/cutting down axle shafts from a B Body to fit in an A body 8 3/4. So that's turned me to looking for an 8 1/4. From what I've read, I should stay away from a 8 1/4 rear ends with a 2.45 gears since I would need to buy a new carrier when installing a higher ratio. I'm not concerned if I find one with a sure grip or not since it would almost certainly have to be rebuilt/replaced.

I'm heading out on a treasure hunt for a few parts next week and will be hitting a few wreckers.

1) Do I need to be concerned with casting numbers for an 8 1/4 rear end since casting numbers on an 8 3/4 are a big deal?

2) What would be a reasonable price range for a 2.76 & up 8 1/4 rear end from a wrecker?

3) Anything else I should be looking out for when getting an 8 1/4 rear end?