Stan, I would heartily disagree. Todays engines have a much lower compression ratio than those of yesteryear. Translation? Thanks to Uncle Sammy, and the EPA, the newer engines, while having the same or more C.I., have less power due to the lower compression ratio. They do not have the same torque and power at lower end of the RPM range, but with a rig that has a decent rear-end gear ration (4.10, 4.11 etc) they will pull the loads.
An example that comes ready to mind, an AMC 390 V8 had 10.5 to 1 compression ration on the cylinders, the mandated change (smog, etc) dropped that down to 8.0 (or 7.5) to one, which was evident in the 400 c.i. that replaced the 390. The 390 developed (factory stock) 345 brake horsepower, and the 400 was somewhere around a 100 h.p. less (I don't remember the specs). Of course somewhere in there, the method of determaning BHP also changed, reflecting a lower hp rating.
One of the diff's in 1/2 vs 3/4 ton rigs will be in the axle size (diameter) and bearing size's. Put the same load on a 1/2 ton and a 3/4 ton, and (speaking heavy load here) you can and will get bearing chatter out of the 1/2 ton rear axles, whereas the 3/4 ton will not give that phenominum....but were talking load actually on the rig, not a trailer.
Of course, I expect some to take umbrage at my comments, but it is my own opinion and experience.
