Imagine running a 156,000 mile Chevy Bel Air 4 door with a 2 bbl 283, Powerglide, 3.36 gears and 14 in. wheels at 65mph. I have no idea what it was turning at those speeds, but guess what...17 mpg and ran like a champ. Yeah, it used a little oil but you would too if your valve stem seals were...