71 chevy drive line questions

Hello, I put a 5.3 in my 71 3/4 ton with the nv4500. The u joints on the nv4500 are about 1 1/8 on the bearing cups. My 71 looks like 1 inch. The truck had a turbo 400 and I moved the crossmember to the holes where a turbo 350 would be. Drive shaft is about 2 3/4 short. This is the 2 piece. Would like to stay with the 2 piece type. Question is, Is there a later model truck that will have the bigger u joint that is longer and slide into the splines of the rear drive lne? Is the 4 spd model longer? Thanks, Alan

I'd bet the Allison LCT1000 has u-joints bigger than the THM400 joints. You'll have several length choices too (RCLB, ECSB, ECLB, CCSB, CCLB) that might work. Potential problems are related to the rear axle yoke to DS u-joint fitment.

Then again, an NVG4500 probably has a smaller joint size the the LCT1000.

get some 3150 series ujoints/driveshaft built. Its worth the money. It may require a conversion joint to make it happen but they're worth it. They are 1-3/16 or 1.187 diameter.

^^ you meant to say 1350 joints.