8.75 Rear End for A Body?

Just got back, truns out it is B body. Axle shaft 28 7/8"-perches 44". Wanted $350 told him $250 cause all the extra work it was going to take. Ended up driving off and halfway down the road he called me back said he would do 250. Its the 489 casting. Yeah and its the 4.5 bolt pattern. Did I do the right thing buying it? I mean I think it's going to be too wide. What all would it take use this rear end or should I get rid of it and keep searching?