What kind of gas mileage do you get with your 67-72?
 

... and what is your engine/tranny/rear end ratio? :confused:

I know most people don't care about fuel mileage but I noticed my 68 C10 was sucking gas like crazy so I started checking and am only getting 10.5 mpg.

I'm just puttering around town and to a few car shows now and then, nothing fast or aggressive.

So my setup is a 350 with pretty much stock cam and crappy 8.5:1 compression, an Edelbrock (quadrajet type) carb and headers. The tranny is a Turbo 400/stock torque converter and the rear end is a 12 bolt 3:08 limited slip.

I was thinking this truck sould normally get around 14 or 15 mpg. Maybe it's because the tires are larger and the body is not aerodynamic?




Ok so waddaya got and what's your mileage looking like?

Re: What kind of gas mileage do you get with your 67-72?
 

I have just about the same running gear, but with a 350 tranny. I think the most I've gotten is 12 mpg. Maybe someone else gets better mpg
mike

Re: What kind of gas mileage do you get with your 67-72?
 

I'm getting about the same as you. 60 over 350 edelbrock 4bbl. 700r4 3:56 posi.

Re: What kind of gas mileage do you get with your 67-72?
 

12 to 14 MPG is not out of reach.Keep your tire pressure at the top of the safe usable range for your tires and keep it in good tune and you should do better. I do know that fuel with ethanol tends to drop mileage a bit. Mine is a C-20 with a 327, TH 350 and 3.73 gears. I get about 14 to 15 MPG.

Re: What kind of gas mileage do you get with your 67-72?
 

6-7mpgs :). ZZ502, built th350, 3200 stall, 3.73 posi.

Re: What kind of gas mileage do you get with your 67-72?
 

I have stock 350, stock quadrajet, stock TH350 transmission with .308 gears, and I get between high 12 to mid 13 mpg, depending on where and how I'm driving

Re: What kind of gas mileage do you get with your 67-72?
 

Like my sig says, 400/400THM/3.54 axle, factory equipment, except the engine and trans have been rebuilt. I haven't checked it without the travel trailer; when towing that, I get 7 MPG. I recall my FiL telling me it used to get 13 mpg, but we put a 12" taller camper shell on it, so it's going to have dropped because of that.

Re: What kind of gas mileage do you get with your 67-72?
 

I'm not much help because I really don't care, I just enjoy.
402 /400 /3.08 posi

Re: What kind of gas mileage do you get with your 67-72?
 

Around 14 mpg with a stock 350, 200r4 trans and 4.10 gears. This is mostly around town with a little freeway at 70 mixed in.

Re: What kind of gas mileage do you get with your 67-72?
 

stock 350, 4 speed, 4.57 diff on 8.75r16.5 tyres, if I sit on or under 60, its 15mpg.
any faster and it drops to 12mpg.
Bone stock in every way, 72k on clock, stock Qjet.

Re: What kind of gas mileage do you get with your 67-72?
 

I get 12 ish with the non-ethanol premium I use.

Re: What kind of gas mileage do you get with your 67-72?
 

Really 10 mpg around town is about the norm for a truck made when gas was 45 cents a gallon. Mine gets 12 on the highway doing 60. And that's in 4200lb box.

Re: What kind of gas mileage do you get with your 67-72?
 

71 with 2014 LS 6.0 and 4L80-e trans. 4:10 gears get 16-18 running 75-80 MPH with the AC on.

Ramp truck might get 12 with 350 and a granny 4 speed in it. No idea what rear end gears are.:chevy:

Re: What kind of gas mileage do you get with your 67-72?
 

460 / 400 trans / 373 rearend I cant pass a gas station .:gmc2:

Re: What kind of gas mileage do you get with your 67-72?
 

I’m satisfied if I average 13-15 on the highway. I will stop for gas at 200ish miles, but try not to go less than an 1/8th before stopping. If I put a load, or have long hills, and the ol girl drinks like a sailor on shore leave. Doesn’t matter though, she ain’t goin nowhere:chevy:
I run a standard 350/4bbl TH350, and 3.73 diff

Re: What kind of gas mileage do you get with your 67-72?
 

SWB fleet 1/2 ton, '99 roller cam 350 9.8 compression w/ mild cam, Edelbrock performer intake and AFB carb, headers, TH400 w/2500 stall, 3.54 rear. 15mpg @ crystal 65mph, 11mpg @ 75mph, 10-12mpg mixed driving. 10mpg pulling the race car on a trailer @ 60 mph. 5000-7500 feet elevation.

In my years of engine building I found a typical V8 will get one additional mile per gallon per point of raised compression.......

Steve weim55 Colorado

Re: What kind of gas mileage do you get with your 67-72?
 

I don't want to talk about it!



It sucks now, but used to get a steady 12.5 no matter how I drove, hiway or country roads. It's been more like 10 in more recent years. I put different heads on a couple years ago and now it seems to be just under 10.... '72 K2500 350/TH350/4.10 with 285/75-16 Goodyear Duratracs

Re: What kind of gas mileage do you get with your 67-72?
 

LWB fleet 1/2 ton, 350 300 h.p. cam, Edelbrock performer RPM, 750 cfm AFB, ramhorns ,2.5 true dual exhaust, CH 465 4 spd, 3.73 axle ratio. 15.25 mpg @ 65-70 mph 5000' to 9000' elevation.

All the Best, Dirk

Re: What kind of gas mileage do you get with your 67-72?
 

Hmmm! I guess I'll just some high compression heads, an air gap performer, a 280/460 cam and not worry about it. It sounds like it will probably at least still get 10 mpg with all that, but at least run better. :bo2:

Re: What kind of gas mileage do you get with your 67-72?
 

72 K2500. 350/TH 350, 4:10, 235/85 R16 tires, HEI, Eldebrock 1406 carb, RV cam. 10-11 mph mixed highway and town driving using gps since my speedo is off by about 10%.

Re: What kind of gas mileage do you get with your 67-72?
 

My 70 C10 with 307 4 barrel when new got 16mpg on highway when driven for mileage. I upgraded to LC9 with 65E and now driven for mileage on highway gets 21.

Re: What kind of gas mileage do you get with your 67-72?
 

I don't know if I've said it before, but that is one SWEET truck!. :metal:

Re: What kind of gas mileage do you get with your 67-72?
 

1968 GMC half ton fenderside. Stock 250 six, turbo 400 trans, 3.54 rear end. My daily driver for about 2 years. 13-15 mpg.

Re: What kind of gas mileage do you get with your 67-72?
 

That's the spirit. Just remember - it takes MANY MANY years of spent gas money before you'd have paid what it would have required to have bought a brand new truck today that MIGHT do maybe 5-10 mph better in the fuel economy department. Drive and enjoy :)

Re: What kind of gas mileage do you get with your 67-72?
 

Like to hear from some six-cylinder people.......

Re: What kind of gas mileage do you get with your 67-72?
 

my 67 C10 - 283/powerglide and 3:73 rear. I don't know what it gets but it isn't good! I haven't run the numbers but my guess would be around 10. The gas gauge moves pretty quick.

Re: What kind of gas mileage do you get with your 67-72?
 

‘67 GMC 250 L6, 3 on the tree, SM 3.54 rear end, 15 mpg on the highway.

Re: What kind of gas mileage do you get with your 67-72?
 

Snotty 355 with a TH350 and 3,000 stall. 3.73 butt gears with limited slip.

6 with my foot in it, 8 with it out.

Gas mileage is for Honda's... :lol:

Gary

Re: What kind of gas mileage do you get with your 67-72?
 

Nearly same setup as OP and get 12.5 with non ethonal. Never checked with ethonal blend because it doesn't start as good and rarely use it. Non highway driving with start/stops.
I need to take it for an interstate drive and see.

Re: What kind of gas mileage do you get with your 67-72?
 

Mine is the original 350 V8 with a 4 barrel qudraflood carb and a 350 at trans . Never been into the engine and has 113,000 on the odometer. I drive it like a old lady going to church. at 5200 feet elevation I have seen 11mpg and up to 15mpg The old engine could use a freshen up. The carb was rebuilt and restored to factory specs. I am still running a distributor with points. :metal:

I forgot that this is a 2 wheel drive short bed truck .
Vic

Re: What kind of gas mileage do you get with your 67-72?
 

Before the rebuild, I believe it was in the neighborhood of 11 MPG for my stock 402/400TH. The engine was rebuilt in 1993, punched out and high performance heads off a 60s Corvette/Camaro. I've never checked and haven't cared to, but 8-9 is probably right.

Re: What kind of gas mileage do you get with your 67-72?
 

I feel like I'm at a gas station every 20 minutes...
Big Block Problems!

Re: What kind of gas mileage do you get with your 67-72?
 

I haven't bothered to check my fuel mileage in many, many years -- it is what it is, and it ain't anything to brag on! Many years ago I made a round trip from NorCal to eastern Kansas & back, about 3000 miles or more iirc. This was when the 55 mph law was in effect, and my truck isn't real happy going much faster anyway. I got between 10.5 - 11 mpg on that trip. '72 K20, stock 350 with TH350 trans and 4.10 gears. At that time I was running 7.50-16 bias-ply traction tires on split rims.

Re: What kind of gas mileage do you get with your 67-72?
 

69 shortbox fleetside with a 400sb and a TH350 and a 3.73 posi. Best I ever got was 13 but I only ever saw that once as I recall. Typically 10 or between 8 and 10 when towing one of the cars on an open trailer. The truck originally had 3.07 gears and I had the 400 in there for a short while with those gears, but the mileage didn't really seem to change when I upgraded to the 3.73s. I still have those 3.07 gears lying around if anyone could use them....

The original 307 engine didn't really get better mileage than the 400 I have now, but it was pretty tired when I got the truck. The 400 was pretty much a win-win when it went in.

Re: What kind of gas mileage do you get with your 67-72?
 

THIS!!!:lol:

Re: What kind of gas mileage do you get with your 67-72?
 

Gas mileage! We don't worry about stinking gas mileage!........:ito:

I have a 350/400 with 3:73 rear getting around 8 to 12 mpg depending on how much my foot is in it.:burnout:

Re: What kind of gas mileage do you get with your 67-72?
 

250 Straight Six one barrel with a powerglide and 3.73, got 10 mpg
250 Straight Six four barrel with a powerglide and 3.73, got 9.75 mpg
454 Big Block with two fours and a 4L80E and 3.73 rear, get 9.75 mpg which seems like a bargain!

Re: What kind of gas mileage do you get with your 67-72?
 

250 Straight Six one barrel with a powerglide and 3.73, got 10 mpg
250 Straight Six four barrel with a powerglide and 3.73, got 9.75 mpg
454 Big Block with two fours and a 4L80E and 3.73 rear, get 9.75 mpg which seems like a bargain!

Re: What kind of gas mileage do you get with your 67-72?
 

I've had 4 trucks, all v8, and gotten between 11 and 13 combined. Best ever from my bone stock 307/3ott/3.73 truck, 16mpg, all 60mph back roads.

Re: What kind of gas mileage do you get with your 67-72?
 

When mine was running it had the original 327 in it. I'm working on putting a 350 into it now, but with the 327 I was getting about 12-13 MPG. I could squeeze it up to 14 if I was really careful with the gas, but what's the fun in that?