gas mileage ?? HELP!!!!!

[ferryboatcaptai]

new to this site, my 66 shortbed gets 14 miles to the gallon, i have the 250 with a 1 barrel carb and a 350 turbo tranny , 3;73 rearend . any one know how to improve my mpg . what about changing to a carter carb??
i drive my truck 70 miles a day and it runs great, but the gas is costing me alot. FBC

 

[markeb01]

Probably the biggest bang for the buck is changing the rear end gear. Even a 3.50 would be an improvement, but a 3.20 would probably be more ideal. I faced the same exact problem years ago, when I commuted 70 miles a day in my 1960. I switched from a 3.70 to a 3.08 and it made a huge difference in mileage, but I had a 350/350. A 3.08 behind a 250 six might be too high a ratio. The performance around town might really suffer. At freeway speeds if might be ideal, or it could cause the engine to work too hard by not allowing it to spin fast enough to make its best torque.

 

[drabo]

Consider a 700R4 swap. That extra gear makes a big diffrence.

 

[markeb01]

In addition to the extra gear, the 700R4 .70 overdrive will really drop the final drive ratio as well, if you want to swap to an automatic.

 

[drabo]

The only problem with a rear gear swap is you are going to have to change out the carrier plus the gears. With just the tranny swap I dropped 1400 RPM at 65MPH. I also started with a TH350 tranny and not a powerglide.

 

[66 KUSTOM]

70 miles a day? how about a honda or toyota?

 

[drabo]

66 Kustom this is a public forum and I must ask that you refrain from using any foul language. My kids could see this and be scarred for life.

 

[66 KUSTOM]

66 Kustom this is a public forum and I must ask that you refrain from using any foul language. My kids could see this and be scarred for life.

hahaha, thats hillariouse!!!!! to funny man, sorry, ill watch what i type. No more foriegn words from me!!!! in my defence i will admit it has been several years since ive owned a foriegn car. (besides dirtbikes but theres no US manufacturers for those)