If your rear has been changed to 3.55, why do you want to get rid of it. If you go to a 55 to 57 you will have a 3.90 which will result in higher engine speed. I'm not real sure I understand what you are trying to accomplish. If you look at the spring hangers you have with a torque tube, you will see that you have a pivot at the front of the axle seat. If you take away the torque tube, you have to get rid of the pivot which is most easily accomplished by welding it tight.
