rear end question?

on the side of your chunk, it will have some numbers, 741, 742, and 489 are the 3 numbers. If you are getting the whole chunk, those numbers don't matter. They have to do with physical size of the pinion. 489 is the strongest, but unless you are turning some serious horsepower, you should be fine with any of them. You need to know the gear ratio though (probably want that to match yours pretty closely), and the size of the yoke for the u-joint (there were 2 sizes I believe)