My 68 barracuda with a fairly worn 318, stock cam, stock heads with 340 valve springs, performer intake,670 holley, dougs headers, 904 with 2800 stall, 3.23 gears and 26” tire will still get around 16-17 mpg at 60.
2003 dakota with 3.9 5spd, 3.23 with 29” tires and 375,000 miles still gets...