rearend brakes??

Depends on 2 things- 1. Are your new axles 5x4" (sbp)? If not, you'll have to switch to BBP brakes 2. Length of the axle. SBP brakes are narrower (either 9x2" or 10x1.75"), so the axle length is different. If your new axles were intended to have 10x2.5" brakes, you can't use the stockers. And, you can't use the backing plates even if you already have the 10" brakes, as the offset of the backing plates is different.

Most new axles have the larger 5x4.5" pattern. If your supplier says you need the bigger 10x2.5" brakes, then you probably do.