I "third" using the 3 speed column shifter with OD.
I will give you another option. Find a 1957-1959 gmc 1/2 ton with a 3 speed. The 57-59 gmc trucks ran a spicer rear with 3.08:1 rear gears. I had that rear and a 3 speed with a 270 6 cylinder in my first truck. I never did understand why so many people were complaining about not being able to drive the freeway.
I bought a set of 3.38 gears for my current 59 gmc 1/2 ton. My 447 inch pontiac v8 motor destroyed the axle. I currently have 3.7:1 gears in my 59 with a .73 OD. Sometime in the near future, I will be changing the gears to 4.3:1. I want a little bit more grunt from my truck.
Higher gears like 3.08 are great for economy, but poor for acceleration and towing. Lower gears like 3.90 and 4.11 are great for acceleration and towing, but not so good for cruising or economy... unless you have an OD. 3.90 gears with a 27%OD will feel like 2.85 gears in OD. 4.11 gears will feel like 3.0 gears in OD. With an OD you get the best of both worlds. If you crunch the numbers, A truck with 3.90 gears and od will be tacking less than a truck with 3.08 economy gears and no od on the freeway.
Tire size will also affect gearing. In my case I had 28 inch tall tires with 3.70 gears. When I changed to 31 inch tires, it made the 3.70 gears feel like 3.34 gears. There was a "loss of gearing" when going to the larger tires. In my case the loss of gearing was not desireable. Changing my 3.7 gears to 4.11 will put me back to where I started. Changing to 4.3 gears should make my truck pull a little better than before.
