My car has a new 9" housing from John's 9 inch factory. The T-bolts are 3/8"-24 and they are not a press fit, they are loose. Too bad the axles were not new. They were piece-of-junk salvage yard axles, shortened and resplined. The axles faces had 3-4 times the allowable face runout - about .015". That made the rotors have at least twice that much runout. New Currie axles fixed that - another $400 down the drain. The axle change did give me the newer SET 20 bearings that uses gear lube as the bearing lube. There is no longer a seal inside the housing to keep the lube away from the sealed bearings. The seals are now mounted at the outside face of the axle housing.

Currie Enterprises. CE-CTFLB29 - CTF Axle Shaft Kit (LB, 29" Long)