[boxmonkeyracing]

with proper gearing, drag coefficient, and AFM. 30mpg is just the starting line. like dragon said my 98 z28 M6 ls1 was getting 27 mpg high way. that was going up hill most of the way. from elevation 200 ft above sea level (fayetteville, nc) to 1700 ft above sea level (boone, nc) in about 200 miles.

but with that being said, my 2007 1500 ext cab silverado with the 5.3 v8 (AFM) gets a combined highway city of 18-19mpg. it's rated at 22 mpg highway and 17 or 18 city. So yea crappy numbers but I've watched my mpg drop from 22 mpg (while driving on a highway) down to 18 in a few mins once I hit city traffic. but it stayed around 18 until I got out of the city and slowly came back up to about 19.5. at least it aint 8mpg city (my Z28 always got that. wonder why? lol).