I have a '62 with an sm420 in it. I have already purchased a t-5, the one with the 3.76 first, and the .72 OD. The OD is not the only consideration. The extra usable gears below 4th help alot. Acceleration is very much improved, and the wieght is reduced as well. I'm sure that shifting will be easier as well. I'm certain that the t-5 will be the single best improvement I'll make to my truck.
