8.8 swap

Well I just bought one from a local salvage yard for $150. I already have an A body 8.75 but the 489 housing has 456 gears and I really like the idea of 4 wheel disc brakes and the 5 x 4.5 bolt pattern. They had 3 explores there and all 3 were different tags. One was 3 73, one was 4 10, and then the last one we looked at was 3L73. Car had 159K on the odometer. What all should I look out for to make sure the rear end is in good enough shape to justify the purchase?