New 8 1/4 rear

Bought an 8 1/4 from Texas Acres. I have some question's. 1) how do I find out the gear ratio? 2) since it already came out of a 74 Plymouth A body, do the axle brackets need to be relocated? or are all a-bodies set up the same for the leaf springs? 3)I was also wondering if I would have to make new brake lines? and finally, how do I tell if the rear is good or not?

Didn't mean to bombard you guys, but I was reading some other posts about leaving the 7 1/4 in the rear, and what could/does happen to them when the go out.

Thanks
Mick