If you are getting a Chevy NV4500, then all you need from AA is a bell housing to use your mechanical clutch linkage. A NP208, NP241 passenger drop, or a NP205 round pattern will bolt on to the rear housing of the NV4500. The only problem is that the NV4500 shift tower is further back than what the SM465 tower is, so the TC shift linkage has to be moved further back. The NP205 shift linkage would probably be easier to relocate. IMO, I would overhaul the NV4500 before I installed it. Unless you drove it prior, and knew it's condition. I really like the way the NV4500 makes my truck feel and drive. I'm running 235x85R16 tires considering the overdrive, I would run a shorter tire to get more out of 4th gear.