A friend has a 59 REO dump truck that he converted to a 5. 9 from the original 200 hp REO gas engine. I think the Cummins is about a 230 hp version as it came out of a bus -- it is intercooled. He had to change the rear on the truck as the gas engine ran a too high (numerical) rear to suit the Cummins. He runs an eight speed transmission (Road Ranger) with a two speed rear. The truck works regularly and grosses in the 30K range when loaded. Fuel milage has increased and it will pull much better. Looks good too and sounds great!!