question for the modded suv owners

[Z-56 Hoe]

My wife is right. Also if not properly tuned that's gonna hurt it too I get horrid gas millage in town but awesome highway and I have a camed 6.0L. LT headers 4L80 trans a converter with a 2800-3200 stall and a Walbro 400LPH fuel pump and 4.10 rear gears and 275-55R20's for rolling mass.

Our SUVs are 6700 lbs curb weight.

I get 19-21 highway and between 9-12.2MPG in town

 

[Big Buttons]

How bad is bad for you mpg wise? I have headers, large cam, CAI, and Blackbear tune, and get around 13 city. Not bad for having 400+hp along with a 500lbs stereo in the back. I'm about to do stall and 4.10s with a locker.