Best MPG for a 4wd 67-72

[shelby987]

I am going to try and start two threads here, not really a poll, more of looking to set the bar for MPG (which seems to be a big topic of discussion these days).

I wanted to know what is the best MPG you have gotten with your 4wd, and what your setup was....Tires, lift, transmission(auto/manual/OD's), gears, engine (details such as ele. fan, carb/efi/tbi, exhaust, hei, etc). I know there are people on here with small V8's, I6's, V6's, Diesels, just trying to see what combinations produce the best results.

I have put this in both posts, if we could keep this on topic with regard to what works.....I don't doubt there are many of us that are unfamiliar with how to get low MPG #'s......are there really many of us who can't push that tank down to 8mpg if we try hard enough? If you have pulled numbers that are worthy of "impressive/above average" let us know the formula.

[Stocker]

Only time I've really checked was years ago on a ~3300 mile Norcal - Kansas - Norcal winter trip (about a couple hundred miles with hubs locked in), averaged 11.5 mpg at ~60 mph.

Stock truck (in sig) then had 8-ply 7.50-16 Armstrong mud-n-snows and an old, heavy camper shell. Oh yeah, 4.10 gears and dual exhaust.

Side note -- with 3 tanks, I once put in just over 50 gallons of fuel. Wouldn't want to do that very often at today's prices!

[ckhd]

'69 K10 short bed. 350, Q-jet (WELL tuned), HEI, 4-speed, 31" bias tires, 3.73 gears, 800 mile trip -- 19mpg average.

[JAKES 68GMC]

I don't know what I get for mileage but it isn't much!

[1969K10]

350V-8, sm465, rockwell 221, 3.73 gears, 33" tires, and I average 14 MPG. and it doesn't vary much when loaded. still pulled 11 MPG in the mountains bar-towing a 68 long C10

[JAKES 68GMC]

Originally Posted by 1969K10

350V-8, sm465, rockwell 221, 3.73 gears, 33" tires, and I average 14 MPG. and it doesn't vary much when loaded. still pulled 11 MPG in the mountains bar-towing a 68 long C10

I would KILL to get that kind of mileage. 5 gal. of gas doesn't last me long camproad bombing. I can watch the needle go to empty.

[special-K]

The less I drive,the less gas I use.That`s economy!

[ChevyDude]

Mine got around 14mpg,... mild 383, turbo 350, HEI, 373 posi

[jamie72]

i`m guessing i get about 16-17 in my blazer, stock 350, stock 4sp,with 33`s

[junkyardjohn]

I JUST SOLD MY DAILY DRIVER OF 10 YEARS. IT WAS A 71 BLAZER WITH 350/350 & A NP205 & 3.08 GEARS THAT CONSISTENTLY GOT 28 MPG. SUUUURRRE !!! I THOUGHT I MIGHT AS WELL CHIME IN BEFORE SOMEONE MAKES SOME UNBELIEVABLE CLAIM OF GETTING 19 OR 20 MPG. EVERY ONE OF THESE TRUCKS THAT I HAVE OWNED OVER THE LAST 21 YEARS (& I'VE OWNED A FEW) HAS GOTTEN 11 OR MAYBE 12 MPG IF THEY WERE PROPERLY TUNED, HAD A TAILWIND, & WERE GOING DOWNHILL. 2 OR 4WD. LOADED OR UNLOADED NEVER MADE MUCH DIFFERENCE. I JUST DROVE MY 69 SMALL BLOCK TOW TRUCK OVER 2300 MILES, TOWING MY 72 PICKUP & AVERAGED 11.5 MPG. WOW!!! I NEVER THOUGHT ABOUT IT BUT THATS 2 TRUCKS MOVED 11.5 MILES FOR 1 GALLON OF GAS = 23MPG. HOLY SMOKES I THINK I JUST FOUND A WAY TO DOUBLE YOUR MILEAGE. THE MOST HONEST GUY IN THE WORLD WILL GROSSLY OVERESTIMATE HIS TRUCKS HORSE POWER & GAS MILEAGE. SEEING IS BELIEVING & I'M ONLY GOING BY MY ACTUAL EXPERIENCES. JOHN

[special-K]

I got 15mpg(95+% hiway)consistantly from a`71 K/20.The fuel gauge didn`t work,so I wrote it all down.And,was proud of my "built for economy & power" motor.The truck had 4.57 rears and 14.50/37x16.5 bias-ply Armstrong Extra Tractions.Yes,I did compensate for the tire diameter in my calculations.It was a 4spd and the motor was a 307,RV cam,1.94" heads,cast iron manifold/Holley 450cfm,HEI/curved & weighted,Accel coil,headers/duals,flex-fan,dbl-stacked K&Ns,balanced/ported,and 9.5:1.
The idea was build it to get to speed and roll with little pedal.The low gears,torque cam,and good flow helped to get it there and keep it there with those tall tires.The tall tires were like o/d.I never used the secondaries,unless I felt like it.It was running on less tham 200 cfm.The fuel was given an easy way to the motor.This also made for great power when desired.And,of course,the direct lock-up and control of the manual trans came into play.BTW,it was back when the limit was 55 and I rolled @60.

[see ten]

Well year before last when going to the Nats we took both of our trucks. I filled them both up and wrote down the mileage. At that time the odometer wasn't working in the K10, of course it would have been off anyway due to the tall tires. The C10 pulled 14.75 and the K10 pulled nearly 13mpg (something like 12.8 or 12.9). This was mostly running on the interstate in the left lane driving like I stole it. The K10 has 33x12.50 Mickey Thompson Claws which I am sure hurt my mileage (my brothers Blazer lost 2mpg when he went from an all terrain to a Bogger). The engine is a 350, trans is a 3sp manual, gears are 3.08. My engine driven fan has been removed and I run dual electrics. I also run a HEI, Edelbrock intake, roller tip rockers and comp cams 4x4 camshaft.

[hevy_chevy67]

I havent bothered to check much, but I got 12mpg once with my 71. Its a shorty with a 350 TPI, 4-speed, 3.08 gears.

[TP from Cntl PA]

I got 10 on a 100 mile drive with the 454 in my k-20 with a 4spd, Haven't checked exactly what gears are in her...........Pretty good I thought, just didn't have the low end I love..........

[hilljob26]

well,i really only drive mine around town,its a 72 350/350 w/ a 208 and 308 gears w/ 35's,it has a 20 gallon tank and i get about 140 miles a tank so im guessing thats about 7 mpg,i sure wish i could make that better,but hey,the trucks paid for so its not a big deal i guess,but any help would be appreciated,im kinda wandering what 373 gears would do....mike

[musclecarfreak]

Mine has not been driven to work since the last time it snowed........At 3 bucks a gallon it would cost me 20 bucks a day to drive it! Looks cool sitting next to the out building though. 4.10's and 35's with 11:1 compression might have a little to do with the poor mpg.....

[72gord]

Hey Hilljob, just my opinion, but I would go to 4.10's with those 35's. Just lugging the motor too much IMO. My 72 had 4.10 and 30 inch tires with a 350/4sp 2 barrrel carb (stock motor) and it got around 12 to 13 empty and 9-10 pulling the trailer. Yea it run some high rpm's but it wasn't working the engine much and I never went over 60 mph.

[Huck]

My 72 blazer with performance built 350, 4spd, 373 gears and 33" tires gives me 13mpg! It has HEI, edelbrock carb and intake. Believe I might be able to gain 1-2 mpg with a stock intake and another 1-2 with 307 gears which I am trying to make happen. Would love to convert to some kind of overdrive but the cost would mot justify the savings on a garage queen.

[knsmodels]

My daily ride 72 k/10 with stock 350/4spd with 4:10's and 33" tires get 12-13 highway.......speed and load dont seem to change it much.....around town if I play to much with the 4spd I think I can watch the gauge move....

[Buckman]

I have a 71 gmc short w/b 355/w 700r4 with 3:73 I get 14 around town and 16.4 on the interstate.

[special-K]

I think with the weight and boxiness of these trucks,there`s a limit @ 3.73s for tall gears.Different tires and torque of engine varies results.But,the tall gear theory goes out the door with these trucks past a good pulling gear.

[Jim_PA]

Sorry to break your rule of being on-topic, but to put this in perspective, my 99 jeep grand cherokee v8 gets 16-18 AVG mpg in mixed driving, with me trying to be light on the pedal. What I'm saying is that those of you getting 14-16 should feel pretty good that a heavier boxier older truck can pretty much keep up with supposed better technology

[avejoe]

I gave up on trying to figure miles per gallon, I go with gallons per mile. The math is a lot easier.

[JAKES 68GMC]

Originally Posted by knsmodels

around town if I play to much with the 4spd I think I can watch the gauge move....

How do you "play" with a granny-gear 4-speed?

[special-K]

Originally Posted by JAKES 68GMC

How do you "play" with a granny-gear 4-speed?

In 1st you can get rubber hitting the throttle AND letting off.
Screech/Scurch..Screetch/Scurch..Screech/Scurch...Kinda hard on`em though .