What is average mpg for 6.2L V8?

[elbowroom]

I have a GMC Value Van 3500 and I would like to know what is the "normal" mpg?
Based on the only trip I've taken in it so far, it was about 12mpg. But that was figuring that because the gauge read 1/2 full, it actually was.
And does anyone know how much fuel the tank holds?
I'm selling my van and I'm not planning on filling it up...half a tank was 50
I appreciate the help.

[Subzilla]

Depends on lots of varibles such as transmission, gear ratio, weight of right foot. My Sub use to get 19ish but now gets about 17 with 700r4 trans, 4.10 gearing, 33" tires (just put on 35" so the jury is out on those). My Blazer will get 21 city/ 24 highway with 3.73 gearing 700 trans, 32" tires. 12 mpg seems low but I'm not sure what a "value van" is.

[Frank M. Hardcastle II]

12 MPg does sound low but in my case very accurate. 1984 GMC C3500 Crewcab Dually. 6.2L Banks Turbo, SM465 4 speed with unsynchronized granny low and a 4.56 ratio rear end. I recently changed the rear end to a 3.55/3.54 (one or the other ). Haven't had much of an opportunity to check the mileage but it appears to be around 14 MPG now. Trying to save my bottle caps for a NV4500 5 speed with O/D. My RPM's showed 3200'ish at 65 MPH with the 4.56. Now it shows 2500'ish at 70 MPH.

[t rex 7]

30 MPG, yes 30, its an 84 C-10, with 700R4, 2.70 rearend. Dual exhaust with glasspacks sounds like the old yellow cool bus runnin thru the hood.

This is if I drive it like I have an egg under my right foot, if not and I drive like I stole it, then 20-22. One trip from Jacksonville NC to Houston I filled up in Atlanta just for kicks and rode all the way home without refueling speed was 70-75(dual 20gal tanks). :D Gotta love that 275 AC!:cool:

p.s. tires arent stock size, they are +1 size bigger than 235s

t rex 7

[More Power]

If the van has a newer 6.5 turbo engine, but you're running it NA, it'll produce less fuel economy than the original 6.2. The difference between 65-mph and 85-mph in a 3.42 geared 700R4 equipped pickup is about 7 mpg (24 vs 17).

Jim