Re: Fuel efficiency...what MPG do you get?
 

I borrowed my dad's 2014 C10 (do they still call them c10's?) 2wd, small v8, for a highway trip and got 17 mpg @70 mph with cruise on and tach about 1600 rpm's. Any square getting close to that is getting phenomenal mileage imo. My 76 GMC K15 with 350/th350 308's can knock down 11 mpg all day long. 65 mph is around 2500 rpm's on the K15.

Re: Fuel efficiency...what MPG do you get?
 

My rig: 1977 C/10 Step side, 454, TH400, 3.73 posi, P275/60R15 rears (28 inches) I get around 8 mpg in town and about 12 mpg freeway.

Re: Fuel efficiency...what MPG do you get?
 

My 1984 K5 completely stock with 31 inch BFG AT's and CCC and CA emissions gets around 14 MPG highway. My 1986 K10 SWB on 35's and with 4.10's gets around 10 MPG. Both 350's and 700r4's.

Re: Fuel efficiency...what MPG do you get?
 

I am on my first full tank since getting this short bed diesel (6.2) on the road. 700r4 with 3.08 gears. I will report my results once I fill up next.

Re: Fuel efficiency...what MPG do you get?
 

I'm lucky if I get 10 mpg with my 82 Stepside.
350 Crate with Carb
TH 350 Trans
unknown rear end, no emissions equipment.

The cat was just removed and carb just replaced so time will tell if my mpg goes up.

Re: Fuel efficiency...what MPG do you get?
 

I get terrible miles per gallon but I get lots of smiles per gallon...

Re: Fuel efficiency...what MPG do you get?
 

Set my float up higher in my Mighty Monojet, and lost .83 mile per gallon. Gained a bit of advance, and a bit more pedal response, so I can live with it. Stumble is gone now, too.

Behold, 250 cubes of fury!

Re: Fuel efficiency...what MPG do you get?
 

Filled up today and calculated. For a mix of highway and city driving I got 20 1/2 mpg. Not too bad for a 30 year old brick. I need to hook up a temporary tach so I will know how many rpm it is running at highway speed. Around 1800 is where they make their peak torque and I am running 3.08 gears. Might need to re-gear once I found that out. I have new injectors on the list of things that it is getting. I am sure that can't hurt anything.

Re: Fuel efficiency...what MPG do you get?
 

Wow! That is impressive.

Driving like I had a load of nitroglycerine bottles on board, I got 16 mpg yesterday on a 80% highway miles run to Greenbelt MD after I switched from heavy 33x12.5 15 tires to 235/75 r15 Goodyear Wrangler AT's inflated to max pressure (and then maybe a few PSI on top of that.)

Does anyone know the impact of fuel temperature on mileage? My fuel line passes perilously close (1/2 inch max) to the right header on its way to the fuel pump. (It actually touched the header when I bought the truck, which may have explained a lot about the way it ran for the PO).

I felt the rubber fuel line from the fuel pump to the carb yesterday, and it was VERY warm. Would my fuel mileage go up if I rerouted the line away from the header and used insulated line from the pump to the carb?