They're right, the Mack's are a hardier engine, take alot of abuse, and supposedly the M-54's with a Mack are worth a grand or so more, while the Cummins, well, its Cummins, working on a reputation from years ago, though its probably due to the EPA regs. But seems of late, all their recon parts etc, come out of Mexico and have a real quality control problem. The only thing worse would be a Cummins Marine Engine, turns to crap without being eaten first, know this from experience (my present job) and the Cummins distributor loves it. They're right about buying a complete unit too, I've got a 1952 M-62 International with a Continental R6602, gas engine, got it for the right price, so can afford to play with it, and its a hobby for me, the search for the parts is the fun of it, but it can soak up alot if you're not careful. Mine was WELL USED by a previous owner, and had no kit. But believe it, the wife approved of the purchase when I told her that the AAA Plus wouldn't pay for hauling the M-54 or the 1942 CCW GMC 5 ton home because they have duals and do not fit a roll back. (but supposedly they will haul my 725's, havn't tested THAT theory yet though)