I'm just wondering what everyone is getting as far as mpg out of there inline 6s. Mines a 79 F150 4x4 4spd and I only get 9 mpg. And yes I know its about the way you drive. But I've went on "economy runs" and only managed 11mpg. Is there anything I can do to make it any better? I'm running a stock 1bll carb.

 

Geez, my buddy with a 390 and 35" tires gets 9.

What are your cruising speeds/RPM like?

 

I had an 84 with a 6cyl and it got 12 mpg. Great motor, but with that kind of mileage, I opted to go after a V8 once the 84 ran its course. There is a site dedicated to the Ford inline 6. It has some good info on 2, 4 bbl carbs and improved exhaust. Only problem with that is if you are governed by smog regs.

 

I have a 79 f150 300 4spd 4x4 shorty with all the smog crap. When I torn it down for a frame off I was getting 15-16 mpg on the highway. I lived in the right lane and if I remember right 55-56 mph was 22- 2300 rpm. Its been apart for about 15 yrs now. It was completely stock and that was my second motor out of a JY. Tires were 33's.

 

I usually cruse at about 65-70. Just seems like that's where the trucks happiest. And if I run at a steady 55 I get 11 mpg. And I couldn't tell you the rpms because my truck doesn'thave the gauge.

 

Around town, C6, needs minor tune-up, 2.8 back end and rarely over 50 I get just a tad under 10 - 38 gallons ran me 358 miles to bone dry. Also think I have a minor vacuum leak. So running well not perfect through a power-hogging auto is close to yours.