[POWERSTROKE]

MY 1979 WHITE Road-Boss 2 would run 67 mph up a surprisingly steep hill about half a block long. It had a 320 hp 903 Cummins V-8 and 6-speed Spicer Trans, with 2600 rpm and 4.44 gears and 11.00x22.5 drive tires it only ran 67 mph anywhere. Bare tractor weighed about 14,000#. Most nights climbing that hill I was getting pretty low on fuel, probably only 20-30 gallons in a 150 gallon tank.
With a 478 gas V-6 high rpm and close gear splits would be a big advantage. I drove a 1978 FLEETSTAR IH with a 478 gas V-8, straight 5-speed, what little I bob-tailed with it, it seemed reasonably quick up to 65 mph. Biggest problem was the rough ride and lack of weight on the drive tires.
Seriously, I watch a show, ENGINE MASTERS a lot! Their favorite engine above ALL others is the big block Chevy V-8, the bigger the better. Anything over 500 Cid or as big as your bank account can handle will be good. OR a Ford GAA WW#2 tank engine, 1100 Cid all aluminum DOHC V-8, 500 hp @ 2600 rpm and 1050 #/ft torque @2200 rpm, and only 1470 pounds dry weight.