I think it'll work. In my reckless youth I lowered the back of my '49 Chev fastback 6" by stacking 2" blocks on top of 4" blocks using extra long U-bolts. It also had a torque tube, no problems. The car still had a mean rake with homemade dropped spindles and 2 coils cut in the front end. Needless to say, there were a lot of driveways and service stations I had to avoid.