I agree. Your wagon may have a 2.93 or 3.23:1 axle. Adding .73:1 overdrive (making 2.14 or 2.36:1 final drive) may reduce torque in high gear and slow the engine down a bit too much for towing, you'll be reaching for direct (3rd) frequently. The A-body 3.09:1 4-speed may be a better choice.
