[undy]

Knowing what engine you're hoping to install Kev I'd steer away from any TR3550s and T5s, just no where near enough of a high torque rating. That leaves the TKO600, T56 Magnum or a B/B top loader. I'd have mentioned the TKO500 but you don't need that deep of a first gear for a big block, especially at the cost of 100 lb ft less torque rating. I've a TKO600 in mine and couldn't be happier with it.