I likely still get 20 mg on the hwy but in the city you can A camm'd car with an SS4k will make your eyes bleed if you calculate in town mileage.

 

Wow y'all get Awsome mileage. With my old ls6 H/C/I setup it would get 9-12 mpg city, and around 24 highway. 17-19 mixed

 

now that's what I'm talking about.

 

Same here

 

I get about 100-120 miles to the tank. According to google, my fuel tank is about 16.8 gal tank. So that's about 5-7 mpg in the city for me. And I'm on a stock rear and small *** cam w/ stock GM 243 heads.

 

right now my cam only(238/242 .605" .610") 98 WS6 (6 speed) is getting around 18 in streets and 21 highway...

..my 04 GTO, before i sold it, was getting 31 mpg on highway usage and averaged 21 on streets..that was with stock stall and the Teaxs Speed Head Cam Package...Torquer V2 and LS6 style Stage 2.5 PRC heads...and a very good tune putting done 427 to the wheels

 

I get 23mpg on the highway with no issues