Diesel vs gas......................

You still have not answered the question. If the big block has more horsepower, why is it not rated to tow more than the diesel?....Since you feel that horsepower is the "only" way to measure engine power, I find it interesting that you can't explain why the lower HP, yet higher torque diesel has the superior tow rating.

I'll answer that, or at least try to.

As we all know, many, many, MANY factors go into tow ratings (I'm strictly talking about GCWR, not GVWR). GCWR rating is based mostly on how much weight the drivetrain can handle. How much weight a drivetrain can handle, is determined by several factors, not the least of which is - LONGEVITY OF SERVICE (how long can a drivetrain generate a given amount of power before wearing out).

It IS true (no matter what diesel disciples will try to say), that the more horsepower you can generate, the faster/better you can move a load. As has been said many times, you can generate horsepower two ways - high torque at low rpm, or low torque at high rpm. Both ways, generate the same horsepower. However, typically, the former of those (high torque at low rpm) is more efficient, and likely to last longer in reciprocating (piston) engines.

As I said, many factors about the drivetrain are considered, for GCWR rating. Longevity of service is one of those factors, and is why the diesel has the higher GCWR rating. It (diesel) can handle the higher load, without wearing out as fast. Yes, the gasser can generate more horepower, and could handle more GCWR load than the diesel, since it has more horsepower. But, the gasser would NOT LAST AS LONG as the diesel, since the gasser would have to turn 5,000 RPMs all day in order to do it.

Still, it is quite possible to build the gasser V8 so it COULD turn that fast all day, and still last as long as the diesel. Would use up obscene amounts of fuel, but it could be done. If it was built that way, the gasser WOULD indeed have a higher GCWR rating than the diesel, since it has more horsepower.

But, as many have said, it gets into economics - a big block V8 gasser that could turn 5,000 RPMs all day long and still last 200,000 miles, would be a VERY expensive engine to build, and would cost too much to put in regular production trucks. Much cheaper to just give the gasser a lower GCWR rating and gear it to not turn so many RPMs. Then, offer a diesel engine with a higher GCWR rating, since even though it has less maximum horsepower, it can still generate enough horsepower to move the bigger load, and do it without twisting as hard.

Anyway, hope that answers the question, bluenote.

Will