Damn Steve. I can see why your wife took away the checkbook.
Have you got 100 miles on that engine you just put in? You really need to drive what you have for a couple of years before changing it again.
My 40 with a 2004 5.3 got about 14 mpg. That's mostly around town with a th350 trans, 4.11's, 35 MT's and a heavy right foot.
A friend that has a 5.3 Tahoe says his wife gets 20 mpg driving it.
My 40 with a 2f gets 13mpg average for a light wheeling weekend.
My wife's lowered 2wd Suburban with a 5.3 can get 22mpg on a long freeway trip.
Point being that the shape of the truck makes more difference than the engine.
That was my point. Like the Tahoe has overdrive and street tires too. Basically saying a 5.3 can do better than 14. The 40 is not a vehicle built for mileage though. If you are concerned with gas mileage, a V8 Cruiser may not be a good choice.
my brother posts here as effjay76, hes got a 350 with a edelbrock performer 4 barrel, toyota 4speed, 35 inch muds. hes at 14 on the highway......you got robbed bro.