DerekTheGreat
Forum Regular
1989 K1500, short box regular cab. Stock 350 TBI & 5LM60 transmission, 3.73 axle ratio. Forget the tire size but they're stock as well. Base timing set to 1 degree. Stock exhaust, stock cat & don't know if it's 2.5" or 3"
Haven't done a pure highway tank in a long time, yet lately I've been seeing 16.2 - 17.1mpg (mostly 16.3-16.8) running about 30% city/70% highway. I limit the top speed to 70mph and try to keep my foot as still as possible on the throttle. I usually end up flooring it 2-5 times per tank anyway and some times have spurts of 80mph or so. More often I do that, the more likely I am to see lower 16's. Oh, I'm also running the A/C too. When I'd run at 80mph & same mix of city/hwy, I was seeing 15.1-15.6mpg consistently, done without running A/C. In the winter, you can easily knock off 1mpg.
Wife's '92 C1500 regular cab longbox with Leer cap & stock 350 TBI & 5LM60 (Yep, confirmed 5LM..) and 3.08 gears has yet to return accurate MPG numbers. Base timing set to 2 degrees. I targeted 1, yet after tightening up the dizzy it came back at 2 and I was too lazy to adjust again. Just had exhaust redone from manifolds to muffler, including a new Walker cat, all 3". Speedometer is still off by a fair margin and it ends up needing work in which I've gotta run the engine and burn gas..
Haven't done a pure highway tank in a long time, yet lately I've been seeing 16.2 - 17.1mpg (mostly 16.3-16.8) running about 30% city/70% highway. I limit the top speed to 70mph and try to keep my foot as still as possible on the throttle. I usually end up flooring it 2-5 times per tank anyway and some times have spurts of 80mph or so. More often I do that, the more likely I am to see lower 16's. Oh, I'm also running the A/C too. When I'd run at 80mph & same mix of city/hwy, I was seeing 15.1-15.6mpg consistently, done without running A/C. In the winter, you can easily knock off 1mpg.
Wife's '92 C1500 regular cab longbox with Leer cap & stock 350 TBI & 5LM60 (Yep, confirmed 5LM..) and 3.08 gears has yet to return accurate MPG numbers. Base timing set to 2 degrees. I targeted 1, yet after tightening up the dizzy it came back at 2 and I was too lazy to adjust again. Just had exhaust redone from manifolds to muffler, including a new Walker cat, all 3". Speedometer is still off by a fair margin and it ends up needing work in which I've gotta run the engine and burn gas..