all interesting comments, I guess my point of the post didnt really come out right,
It was everyone raves about how much better LS motors are than older small
block chevys and with all the new technology, yes even 20years old, but almost all of
my older lifted less HP and either carbed or real crappy ancient fuel injection got better
MPG and performance. yes 4.10s arent good for gas mileage but if it keeps the engine
in its power band it is good, again my tahoe with 3.42s is out of its power band with 35s
and only 245 hp but gets much better MPG and performance almost as heavy, not much
better aerodynamically. I know there are tons of conspiracy theories blah blah blah about technolgy
being hidden by manufacturers but just would guess you get 17-18 mpg being babied at 65mph,
not 10 or 11, My tahoe can Hummer Not a chance lol

again never bought it for MPG but it is getting real $$ now

 

Pay more accurate comparison would be a mid 1990s crew cab long bed four-wheel drive with a 454. The weight would be close, aerodynamic as well, that it actually makes less horsepower than the 6.0. And you could drive that one all day long with or without a trailer, might average between 9 and 12 miles per gallon.

As far as LS engines being the best thing since sliced bread, I'm not sure I sign on to that. My boat has a small block Chevy, and I don't want an LS engine in it. There's a lot to be said for simplicity, even if it isn't as efficient or economical. All the electronic modules in all the engines today, create issues more than anything. And it's getting worse on the new models. If you like to rebuild your own engines, the small block Chevy is still the way to go. Massive aftermarket availability at an affordable price in comparison.

 

there is no question that the LS engine is more efficient then prior engines, not just more efficient but improved in just about every aspect, oiling system, head design, piston design, etc....
but the MPG numbers didn't change much when they transitioned from the vortec engines to the LS engines (1998 to 2000), what they did see was a jump in HP and Torque for the same average MPG.
the big MPG jump happened when they introduced AFM and VVT to some extent, which only the 08 and 09 H2 was equipped with VVT.

Neal

 

there's been plenty of towing tests done between the 454 and the 6.0 with the 6.0 producing better mileage by a good amount while towing and while making a good bit more HP but down on torque.

I think the H2 MPG is more due to the truck design then anything else.

Neal