I believe your only issue with using the one piece shaft in your application is that it sounds like you have lowered the vehicle and that would cause interference with the driveshaft center support crossmember. I just finished installing a 3 speed overdrive in a 59 3200. We removed the SM420 4 speed and had a drive shaft made with a slip joint. The new shaft was made with a 3 1/2" tube and was 63" - u joint to u joint C/L. The driveshaft shop had no issues with making the driveshaft that length. There were no clearance issues.
If I remember correctly a 55 3200 with a factory 3 speed or 3 speed OD trans uses a one piece shaft. The 4 speed is much shorter and uses a flange, hence the 2 piece shaft.
Fred
Last edited by rfs56trk; 12/31/2016 10:10 PM.
