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

This part of your argument is flawed.

It does not matter which truck/cab configuration you get the Duramax in, all current DMax's are the LLY with 310HP and 605TQ. In addition, all current trucks with the Duramax have the same 3.73 rear gears and all of them with automatic transmissions have an Allison. Therefore, the Duramax will develop that same higher HP at the lower RPMs than the vortec 8100 in all 2500HD and 3500 configurations. The 2500HD and 3500srw trucks both have the same 22K GCVWR that has been available since 2001 with Duramax/Allison and 8.lL/Allison trucks (only when the big block is paired with the 4.10 rear gears). Since it would be nearly impossible to max out the GCVWR on 2500HD and 3500srw trucks without exceeding payload capacity through 5er or gooseneck pin weight, it does not make sense to up the GCVWR's of those trucks with the newest version of the Duramax.

I agree with the first part, but not necessarily the second. Since these trucks are used not only to pull RV's, but also commercial trailers (with a pintle hitch, for example), it would not be unreasonable to assume that the GCVW can be exceeded before the GVW of he truck is exceeded. You may run into difficulties with the max tounge weight, but the GVW sould be fine.

With the 3500drw however, it is more likely that one could get to the GCVWR, while still remaining under payload capacity. Therefore, those trucks are rated for 23,500 pounds of GCVWR with the diesel. So, you have a diesel engine with a 3.73 rear end that is rated for 1,500 pounds more towing capacity than a big block with a 4.10 rear end.

Unless you get the DMax with a manual tranny. In that case, the truck will have the same 22K GCVW as the 8.1.

I agree that torque is a different type of measurement than HP, but when you are considering the application of torque and HP in the case of light duty trucks when towing, the low end torque advantages of the diesel overcome the high end HP advantages of the big block.

Yes, there are advantages. I now have a DMax because of some of them. However, geared correctly the 8.1 will still outpull a DMax because of its higher HP. That may require a 4.56 RE - and the higher rpm that goes along with it - but it can get more torque and HP to the ground than the DMax because of its higher HP with the caveat that it has the proper gearing.

I was merely pointing out that with

ALL OTHER THINGS BEING EQUAL

the higher torque diesels have an advantage when towing, even though they have less horsepower.

And that is where we generally run into trouble. If everything else is equal (especially the gears), then the DMax will have an advantage over the 8.1, no question. If you look at the power curves for both engines, the 8.1 is developing around 250 HP at 3000 rpm (IIRC) while the DMax is developing 310 at the same rpm. That's quite a difference. So, from a dead stop until the 8.1 gets up to around 4000 rpm (or whatever rpm the 8.1 crosses the 310 HP mark), the DMax is developing more power than the 8.1. Any way you dice it, the DMax will walk away from the 8.1 up to that point. Now you may say that it doesn't take the 8.1 long to get up to 4000 rpm. But, if it is pulling a large load, that could take quite a while (relatively speaking).

Bert