I put a T-5 in my 68 Chevy pickup behind a stout 327 with 3.43 posi in the rear. It lasted 3 years and I stood on it regularly. It is a very smooth shifting manual tranny. As soon a some slop developed in it I twisted off the 5th driven gear. Total rebuild by a tranny shop in Memphis. Didn't last 6 months. They rebuilt it and it broke inside 6 weeks. I went with a Tremec TKO 600, direct replacement. I have 12,000 miles on it and have done parking lot burnouts to the max. This tranny is bullet proof! It is not as smooth shifting as the T-5 but I will take the longevity anytime.