So... I got 445 miles to that tank.... About 1.8 mpg increase....

 

do 5.3's have a bigger tank than 4.8's? im getting more like 300 miles a tank and thats 14.5 mpg...

 

yeah mine says I only have a little over 300miles on the range meter when absolutely full. My dad has either a 99 or '00 Sierra with the 5.3 and I know his will hold the same amount of gas. But for some reason his gets better mileage than mine.

 

When it comes to NBS, the shortbeds have 26 gallon tanks, the longbeds have 34 gallon tanks...

Don't go by the range meter. Reset your trip odometer every time you fill up and calculate it that way...

 

I'm pretty sure my tank is 23 gallons

 

Nope... 26 also.