Right. All true. It's not a dollars issue. The issue is getting a configuration that works for my needs. So the decision I'm trying to make is, do I spend a few bucks and simply install the 3.73's in the 1500 Ext Cab 5.3 w/ 6 speed? Or leave the 3.42's as is?
In theory, the 3.73's on the 5.3 motor will provide better off the line performance, especially while towing anything, crisper throttle response at highway speeds, towing or not. Sure, 1 mpg less milage. But that's a trade off I can live with.
Disadvantages to the 2500 HD:
* the 6.0 only gets 10-12 mpg
* it is 1200 lbs heavier than the The Ext Cab 1500 and only makes 45 hp more. 45 hp doesn't push that 1200 lbs.
* ride quality is far less than the 1500
It seems the only reasons I can find, thus far, for GM not offering the 3.73 with the 5.3 is fleet gas milage requirements and an incentive to sell the 6.2. As a daily ride, barring slightly less gas milage it doesn't appear there would be any disadvantages with the 3.73's. It would be great if someone running the 3.73's w/ the 5.3 could chime in. Then again, if there's truly no one who has done it, then I suppose that's a clue that everyone is happy with the 5.3 w/ 6 speed and 3.42's. Maybe that's that's the final answer.
I do intend to ask the service manager at my dealer to call GM support and ask the same question. If I get any useful data back, I'll post.
Last side comment, the reason some of the ratings vary by a 100 or 200 lbs between various configurations is because of vehicle weight. Example, the crew cab is heavier than the extend cab. There are other examples. But that reflects in the numbers too.