My 57 has a 71 350 truck engine. A T5 from a Camaro fits the bell housing perfectly. I put in a new clutch and pressure plate 'cuz I had it apart anyway, but you will find the new T5 has a different input spline than the older trans. In the Tech Tips section of this site, Grant Galbraith has a good piece on mating a T5 to an AD with an in-liner.
