Rick---
My '64 427 came new with a T10. After about a month of driving, I took off from a light, granny-shifted into second at about 4000, and twisted off the output shaft. I was working at T&C Livonia at the time and knew the Executive Engineer. He signed a release for a not-yet-in-the-parts-chain Toploader with a big in-'n'-out and had it sent to the dealer in exchange for the T10. I had to buy the fork, TOB, and disc to go along with it, but I figured it was well worth it. I put in a Hurst at the same time. No more T10s for me. Too marginal on the torque/life.
KS