[cerial]

8.2, 4 speed manual, and 3.08 gears. Should get you in the teens if your under 20k and running considerable mileage.
3.42 if your towing moderate/hilly, under 500 mile round trips, with mileage closer to 10.
3.73 or lower if your more into lighting up the tires then towing.

That 1st gear(granny) and a 8.2 will pull anything off the line up to around 15mph. You won't be wining any races 15 to 40. Or 40 to 60. But, above 60 you can sit back, let the engine run quietly, and have plenty of power on reserve.

You could build a 496 (8.1). But if you look there are lots of 500's(8.2) for around a grand(entire 70's caddy) that could be bolted up to a 4 speed muncie for $500 and get mileage in the teens while living a easy long life.

You can tow with a turbo small block. But your going to end up above 2k and need low gearing to keep the thing in the high rpm range where they make torque. A 8.2 or 8.1 can make torque off idle and build it from there. A diesel can do better at twice the engine weight and maintenance cost.