B body 8.25 in an a body. Help

i believe hes in Novato, which is close to me. the thing attracting me to this particular rear is the fact that its the gear ratio i want (3.23) and its a SG. also says it only has 1000 miles on it

Yeah that makes a big difference. If you can get it reasonable it sounds like a good deal. Another thing to think of is that if it is too wide as is it would probably be cheaper and easier to just buy a new set of back wheels with the back spacing that will put them in the right track rather than tearing the whole rearend down and having it narrowed. Then you'd only have to cut off the spring perches and weld a new set on. Just make sure if you do that to get the pinion angle set correctly before welding the new perches in place.