Gas MIlage

New2Trucks · March 16, 2006

hello i own an 84 GMC 1500 2wheel drive just regular cab/box, itsa got a 250 ci straight 6 in it 3 speed auto tranny, i was wondering what kind of milage i could expect, i was told only about 12 or so MPG, any info on what kind i could expect or what i can do to get better millage would help thanks.

67ChevyRedneck · March 16, 2006

Replace the 3 speed auto with a 5 speed or 700R4 automatic. If you use a 700R4 you'll need to purchase a TV cable kit and Torque converter lock up kit. Check out Bowtieoverdrives.com, they have lots of info there. Also check the rear end ratio. If it's lower than a 3.73 (like a 4.11) you may want to install a higher ratio. Even doing thses things will probably only get you 16 highway and around 14 city.

ProSport Tim · March 16, 2006

From what I've seen no straight six, any make, has gotten decent gas mileage.

New2Trucks · March 16, 2006

From what I've seen no straight six, any make, has gotten decent gas mileage.

<{POST_SNAPBACK}>

ok thanks for the help, ill look into a new tranny

pm26 · March 17, 2006

From what I've seen no straight six, any make, has gotten decent gas mileage.

<{POST_SNAPBACK}>

ok thanks for the help, ill look into a new tranny

<{POST_SNAPBACK}>

Wait a minute! does this make any sense? For the cost of a new transmission, you can buy a lot of fuel. And manual transmissions are morereliable than auto transmissions. Going frorm manual to automatic is not going to do a whole lot for you gas mileage wise. As somebody mentioned, large displacement straight six engines are not fuel misers. I know that the Ford 4.9 liter six gets about 14-15 MPG tops in a 2WD truck.

torx · March 17, 2006

hello i own an 84 GMC 1500 2wheel drive just regular cab/box, itsa got a 250 ci straight 6 in it 3 speed auto tranny, i was wondering what kind of milage i could expect, i was told only about 12 or so MPG, any info on what kind i could expect or what i can do to get better millage would help thanks.

<{POST_SNAPBACK}>

It's more about the body style and wind resistance not the engine. Your pushing a big SQUARE brick through the air and 73-87 body style didn't get good mileage. I had an 87 2wd rc/lb with a 5.7l/350 tbi and got 15mpg highway on a good day and about 10mpg city with an overdrive automatic.

Keep what you have if it runs well. Save those sheckles for a new or newer p/u down the road.