I still have stock axles in my 63. I run 4.30's with a Detroit Locker and 30 x 9 radial slicks on the street. I have 7 years on them on the street with my 493 and about 20 track passes and last time I had the axles out they still looked fine. I plan to upgrade but so far they have held up better then I thought they would. Course my car is an auto car. Ron