Got one in my current truck, a '65 3/4 ton. You will want 4.57 gears because the first gear of the 3-speed is too high. Not sure how it would work with 4.10 gears for taking off, but in overdrive it is a 30% drop in rpm's. It turns those 4.57's into 3.19's in overdrive. So the rear-end gearing is also something to be aware of.
