T-10s were available in Chevrolet applications and others from 57 on to at least '66. It was a favorite muscle-car transmission and appeared in Pontiac GTOs, various MOPARs. I had one in a factory-supplied '66 Bonneville. Notably, they were not available behind MOPAR 413s and 426s. You could get the heavy-duty 3-speed or a Torqueflight. To my knowledge, they were not available in any full-sized pickups. Word on the street back in the day was that the T10 would not withstand the torque of a 426 MOPAR. But then they did come behind 396 and 427 chevs, 421 Pontiacs, 442 Olds (what were they, 400ci ?). So, who knows...
Perhaps for a hot-rod half-ton pickup it could be a good choice but bear in mind that there were two 1st-gear ratios available: 2.56 and 2.20. My Bonneville had the 2.56 low and that was only just adequate to get it rolling despite the big 421. Of course if I burned the tires there was no problem once the smoke cleared.
