the T673C was a great motor. Lots of torque and a great sound. And it would last too! I can't get a good look at the axle hubs. Mack had two types of CONE shaped axle hubs (axle splined on both ends) and I think this truck looks like the 44,000 pound boogie. Mack transmissions (triple counter shaft) and rear ends/axles with the top mounted, duel reduction design was probably and still today if you get it, the hardest to break or tear up in tough off road situations.
w2dmw sure enough, the Dump Mixer series was one of if not the best trucks Mack ever built. We hauled coal mostly off road and there was nothing as tough. Or not much at least.
@asfshrimp Mack T673C 250 hp early 70's motor which later mack turnded it into the famous 350, original motor was a 711 in this truck.. which was not a good motor for mack