3-tons 300 miles with a 235? I don't care what transmission you use, you won't be moving fast!
About a month ago I helped a friend move three cars about 1600 miles. We drove one, a '57 Chevy wagon with a 235 and a 3-speed. It did nearly 20 mpg and kept up just fine.
It kept up just fine with the 350 powered trucks that were each pulling a car behind them. If you're serious about towing over a distance you might want to rethink your motor choice...
