mileage motors

[lukecp]

3.08 was standard on most trucks in the 80's, and I've heard of even 2.73's....with a 700R4. One of my friends had an '86 K10 with a 305/700R4/3.08 combo. With 32" tires it practically idled down the freeway, but got maybe 10-11 mpg going 75, and had no power, with its worn out, improperly tuned 305.

[67_C-30]

I would recommend one of the smaller Comp Xtreme 4X4 cams. They produce great low end torque, and helps the push the truck down road better, The problem with a small cube engine sometimes that that you have to give it lot of throttle to make them feel like thay have any power negating the fuel mileage advantage of having a smaller engine. If you can do it, get the CR up to 9 - 9.5:1 and go with a cam designed for low end power. As Pynotechnic said, I would get a freshly rebuilt Q-jet if you can't go with EFI. 18 - 20 MPG on the highway should be no problem with a high geared rearend.

[oldgold70c10]

My 305 has 189,000 miles on it.
It came from a '77 Monte Carlo.
It was repeatedly overheated on a trip from OK to Calif. & back.
Has only a 2bbl carb
Sat for a year before being put in the truck.
Best milage (after tuning it up a few weeks ago) was 18.6 mpg for 1 tank.
Before it was 15.mpg. In the Monte, best was on a trip from OK to NM was 21mpg.
I am running 3.73 rear gears, stay about 60 on the highway.
Future plans: 4bbl Q-Jet or Edelbrock, 3.08 gears.