Cats were the best. Most costly too. Cummins were much better than Detroit, less costly than a Cat. Good compromise.Some folks swear by Cummins, I've just always had better luck with CAT engines... that 470hp CAT 3406E was a good motor, mine would pull a grade as well as a 500, lol. Great on overall fuel economy too, the 500s, 550s, etc, all sucked fuel like it was going outta style. I liked that 470 CAT, it was a good motor, fairly easy to work on too...