What Tire size to Run with 4.10s

[xKid4x4s]

Hey everybody, I have a 2000 old body style K3500 4x4, with 4.10 Gear ratios, 454 Vortec engine, 4L80e Trans, and it drinks fuel like crazy!!

Now besides knowing that this truck will never be fuel efficient as long as gas is over 10 Cents a Gallon, Id like to know what size rims/Tires should I run with the 4.10 gear ratio the differentials have?

Currently I am running the stock wheel size configuration (sorry Cant remember the size now), and Thought that due to gears etc.. Putting larger wheels on this truck will improve my mileage on the highway? would like to run some 17" Rims with 37" Rubber, but will do what ever is most feasible.

thanks for any input!