I just went through the same problem. 52 F-1 with a Chevy/TH400. You have the 3" output shaft. You'll need a 2 piece driveshaft. Unless your truck came with a 2 piece driveshaft, you'll have to build a carrier bearing crossmember, and the carrier bearing had better be the same angle as the pinion angle. You need a long output shaft transmission, and a 1 piece driveshaft that can slide on the output shaft of the transmission. A lot of guys with GM engines opt for the TH700 4R. It's the same size as the TH350 w/9" output shaft, 4 speed, has an overdrive, and is just as strong as the TH400. FYI...The TH400 will rob you of HP.