Another newbie question, 258 mpg?

[marc]

Another newbie question, related to the fact that I rescued my father-in-law's '84 J10 without researching the vehicle, very stock with the 258 and functioning Calif. snake nest of a smog system. It was an emotional purchase and a chance to get back to wrenching on something other than outboard motors. What is a reasonable gas mileage for "Molly", as she is known in the family? From what I have picked up on line, 10-11 is maybe the standard but I am not sure?

[Stuka]

Depends which transmission it has, and which gears. My old '81 J10 with 31" tires, 2.73's and a 4sp manual would get 17-18 on the HWY pretty regularly (13-14 city). But that was with a Weber 32/36 carb and TFI ignition. The stock BBD is a terrible carb and getting it to run good for any length of time is tough. They are infamous for having idle jets to dribble fuel. So they run rich and don't like to idle.

If you have an automatic, it will be a fair amount worse. 10 around town might not be far off. But 14-15 HWY would be about right.