I get 13 consistantly! 10-12 when pulling the 5er.

 

Its been a while since I posted because I am in the Army and just got sent to Italy this summer. Anyways, the truck is in the garage back home waiting for some paint and a little bodywork. Prior to leaving I had switched over to a Holley 780 as well, and if I kept my foot out of it (with a T-18 4Spd) I could get between 11-13. But the engine needs some work as well. When I get back next summer and get that done I'll keep you posted as to what I did and what differance it made. Good luck with yours.

 

I got 7 1/2 pulling a 8k 5/wheel camper. Can get close to 10 empty. 87 F250 w 4:10 gear. 2WD

 

My 86 F250 4x4 460, C-6, 3:55 gears, Edlebrock Performer, Holley 4160, 600 CFM. I get 9.5-10.5 MPG empty real regular. We own a 10,000# Travel Trailer, and at 65-70 MPH get 5 MPG, at 60 MPH 5.5-7.0 MPG. I have 171,000 miles on this truck engine never had heads off, I'm not sure, but I'm pretty sure, the original timing chain is still in.

 

1997 F250 HD reg cab 4x4 E4OD w/142,000 miles averages 12.5 mpg, unless my right foot get's heavy.

 

What muffler are you using?

 

Running 3.31 gears and a C-6 in a 1977 F250 I get 10 on the highway and 5-7 in the city depending on how hard i drive it. Pulling a car or tractor makes no difference in gas mileage.

 

14.5 best highway(60-65mph), ~10 city, 7.5 pulling 5th wheel ~65mph

 

I got 15.3 at 70 to75 mph in my 78 f150 supercab 2wd tonight. Had to make a trip a little over 100 miles. I was very happy. And this truck is in need of a major tune.

 

I get 7-9 driving with light or heavy foot mixed city highway. I usually get 5.5-6.5 towing.

 

Back in the dark ages (late 60's, early 70's), I worked at a dyno shop and learned to recurve with stock parts. I have several old dist. laying around and I usually just use two of the light springs along with the short advance curve in the dist. In the case of the 460 I used the 13 degree curve (it was in the 18 degree) and replaced the heavy spring with another light spring. Set 8 degree initial timing and get a total of 34 degrees at 3200 rpms. You can adjust the full advance RPM point by tightening or loosening the spring tension.

The muffler is a 3" in and out straight thru unit, but I can't remember the brand. Will see if I can find the reciept somewhere.

 

Hit 10.1 MPG this weekend city driving only.

 

I got 10.8 today on a combo of city and highway and was glad to see it. I wasn't glad to pay $73 to fill up though!

 

Just moved from Cali to Toronto.... Big box on back (raised sides of truck 3ft over bed... biggest dorkiest ghetto homemade cargo shell you have seen) got about 11.5 mpg the whole trip averaging 73 mph.... Mileage was the same going over the rockies, got better on the way down, but the puter freaked out at over 10000 feet.... not enough oxygen, so it ran super lean. Reset the check engine light and mileage went back to normal. Load in the back was light, about 2000.

 

Towed my boat a bit down the hi way didnt like the throttle position showed no vacuum improvement with the 650+ carb. Decided it was time to fix the bowl screw I stripped out and convert the carb back to a 750. Holley's repair kit was 75 $. So for 100$ purchased the Proform body. With all the air flow now that I opened up the exhaust it should work better than before.