I have found it very confusing regarding the gear upgrade from 4.11 to 3.55. For the 37 I am told by the ring gear supplier the ring gear is riveted on, so the actual carrier must be changed as well by substituting a 48 to 50 center and modifying the tube length and spline at the yoke. I know I can get a rear out of a 49 to 54 car with a 3.55 and modify the mounting to get that to work, but do I have to modify the tube length and yoke spline from a 49 to 54 to fit the 37?
