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

[Sparky dave]

350 quadrajet headman headers flow masters performer intake 9.0-1 compression 700 r4. Never left the drive way in a year and spent £90 uk pounds in gas so far 🤪

[garyd1961]

I have a 70 long bed C10 with a L31-R Vortec crate engine. Factory cam, headers, 2 1/2 duels, Holley 770 carb, MSD ignition with a 6AL box, th350 trans, 307 gears. I really don't know what gas mileage I'm getting but I'm happy with it. I would guess it will do better than 15 mpg if I drive it right which I never do.
All I really know is it gets way better mileage than the old tired 307 did.

[72LB]

Originally Posted by Sawlog

How are the rpms going down the interstate?

Don't have a tach on it at the moment but start going over 60 it gets whiny.

[69SCSS]

And I was worried that I swing between 12-14mpg in my truck! I have a 250hp GM crate 350, 700r4, 3:73 gears and 29" tires. As long as I am on the highway it's 14 or so. Anything else and it goes down.

What made me think I could get 17 outta this combo?

[67ChevyRedneck]

1967 C10 (it gains mpg over 69-72s 'cause of the slanted back hood! Aero!)

Had this combo a LONG time now (since 2002). 350/700R/3.73. Great combo for these trucks if you're not into the whole LS thing.

Most of my driving is 45-55 mph around town. I probably honestly only average 11-12 mpg. It does pick up on long cruises. Keep the speed down to 55-60 I can get +/-16 mpg. 60-70 mph is around 15 mpg, and if I push her to 70-80 it drops down to +/-14 mpg. The slant back hood probably does help, but it's still a huge brick.

[72c20customcamper]

Mine is measured in smiles per gallon not mpg.

[69SCSS]

Originally Posted by 67ChevyRedneck

1967 C10 (it gains mpg over 69-72s 'cause of the slanted back hood! Aero!)

Had this combo a LONG time now (since 2002). 350/700R/3.73. Great combo for these trucks if you're not into the whole LS thing.

Most of my driving is 45-55 mph around town. I probably honestly only average 11-12 mpg. It does pick up on long cruises. Keep the speed down to 55-60 I can get +/-16 mpg. 60-70 mph is around 15 mpg, and if I push her to 70-80 it drops down to +/-14 mpg. The slant back hood probably does help, but it's still a huge brick.

I don't know about either what it does in town or highway, but average is about 14. I got 12.8 on the current tank, but I also did a lot of in town driving this week. On my drives to Salem and back I get 13.5-14.5 average when I gas up and check. My GPS speedo isn't very accurate (hard to get a clean signal when you're constantly under a canopy of trees) so I might actually do better than that. I usually add 10 miles to my total when I gas up to get my mpg, but I don't even think that covers it. My GPS speedo doesn't get a signal for at least 5 miles going south from my place!

Yea, I'm never doing the GPS speedo again. That's what a VSS is for.

[t300]

20+. Lq4 with 4L60e. 3.07. once you go LS...things are better.

[Jim Boy]

I don't care what I get with my 250 as long as I get home without having to call a wrecker or do any pushing. Someone earlier said mileage was for Hondas. In 1992 I owned a 92 Honda Civic VX manual trany. The thing was rated for 72 miles to the gallon. I never got that but was close to 60. I had a Dodge pickup that cost me $140 a week commuting to Toronto and back when I was working. 6 cylinder with 4 speed overdrive. I bought the Honda and would you believe $40 a week. No BS. I saved $100 a week, $5000 a year, had the car for thirteen years 780,000 klm. saved around $65,000.00. That Honda was one of the best cars I ever owned. With the 68 truck I'm only giving back what I saved with the Honda. Everything evens itself out in time. If it's running enjoy it. You can't be nostaljack and economical at the same time. Have a good one.

[68Blu]

Running a 350/355 crate backed by a 700R4, Holley Sniper EFI, and 3.73 gears. Currently getting about 12 mpg. Sound about right too you guys?

[Steeveedee]

Originally Posted by 68Blu

Running a 350/355 crate backed by a 700R4, Holley Sniper EFI, and 3.73 gears. Currently getting about 12 mpg. Sound about right too you guys?

Not bad. My setup is in my sig. Do you have a camper shell that is tall enough for your wife to stand up in? I get ten in mixed driving with it. I'm not going to talk about the mileage towing my trailer <cough>7 MPG<cough> because that's towing. Though I did discover that the vacuum advance mechanism was busted, after that. Probably doesn't make a difference, given the engine vacuum I see when I'm towing. Maybe I'll get 8 MPG the next time I drive enough distance to measure it. Good thing I have 53 gallons of fuel capacity with the saddle tanks.

[BC10]

350, th400, 3.42
I get about 11 mpg, but if I have Metallica blasting, I get 9 mpg

[ApacheNick]

72 K15, Trashed 350, sm465, 3.73 gears and 33x12.5 tires.

I get between 8 and 12 in town depending how heavy my foot wants to be.

[Richard]

Averaged around 10 mpg with my 72 K10 when I drove it, empty or loaded. Stock 350, 3.73's and 31" tires. Expecting just a bit more with the new LSA, 5.38's and 40's. But with over 3 times the HP and TQ I do not care. My previous 72 K20 with a slightly warmed 350, 4.10's and 38's averaged about the same 10 mpg.

[Blue GMC]

When I was running the original 292, 2 barrel with the 4 speed and 4:10s 15 no matter what I did driving it.

Pulled that out and put in a 350 bored 60 over Vortec heads mild cam, 600 cfm carb, TH350 stage 2 shift kit and 2500 stall with the same 4:10 rear. Lucky to get 6 intown. I think I have a problem as the last time I had her on the highway went from Wichita to Eureka, KS 67 mile trip one way drained the whole tank at 60 mph and almost pulled over to get the spare gallon out I had in the bed the needle was so far below E when I hit town.

[Ol Blue K20]

Gas mileage? What's that........lol

[tim71]

Originally Posted by 72c20customcamper

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.

My K1500 gets 10.5 mpg. I was in high school during our trucks birth years, gas cost from 28-33 cents per gallon then. A 5 dollar bill almost bought a full tank back then.

[BRL]

350/350 combo 3.07 rear end.

What kind of mileage do I get?

I got a bug.

[gmc684x4]

I used to get 13 to 15 in my 68 k10 350 qjet headers 4 speed 3.73 gears and ran about 32 inch tall tire

I would get less if i walked on it

Building it back into a c10 with l31 350 5 speed havent opened the diff yet to see what gears i have for it yet
Going with a 28.5 inch tall tire keep it stock size and proubly a 2.5 / 4 inch drop

[Ol Blue K20]

Originally Posted by gmc684x4

I used to get 13 to 15 in my 68 k10 350 qjet headers 4 speed 3.73 gears and ran about 32 inch tall tire

I would get less if i walked on it

Building it back into a c10 with l31 350 5 speed havent opened the diff yet to see what gears i have for it yet
Going with a 28.5 inch tall tire keep it stock size and proubly a 2.5 / 4 inch drop

WOW!! Not a lot of rare K models converted to a C. But everyone has their own vision of what they want. Hopefully some of your unused bits and pieces help keep another K live on......

[gmc684x4]

Lol Ol Blue
It was a c model until i got the itch to make it a 4x4 i have several k10s and a k20

I am building up my dads 72 k10 with a roller cam 350 vortec heads be pushing over 400 hp

Going to make it into the lowrider i had originally planed to do when i got it

I learned lots about these trucks from my Late cousin Les

Teaching my 8 year old son how to wrench on them

[Ol Blue K20]

Originally Posted by gmc684x4

Lol Ol Blue
It was a c model until i got the itch to make it a 4x4 i have several k10s and a k20

I am building up my dads 72 k10 with a roller cam 350 vortec heads be pushing over 400 hp

Going to make it into the lowrider i had originally planed to do when i got it

I learned lots about these trucks from my Late cousin Les

Teaching my 8 year old son how to wrench on them

Whew, I was thinking you were nutz....

[68Gold/white]

Originally Posted by special-K

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

Tim, I am sure you have a Quadrajet?

Let me know if you ever want it worked on. Some parts and knowledge from Cliff might help it a lot!!!
Jeff

[Ironhorse]

'71 K10 350/350TH, Performer intake, Edlebrock 625 CFM, 3:07 gears on 31/10.50/15s and get about 11-12 mpg. BUT: The SPM (smiles per mile) are sure numerous !

[Happy_dan]

No idea, I haven't kept track but I can watch the gauge drop as I drive.