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08-16-2020, 10:15 PM | #76 |
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Location: Modesto, CA
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Re: What kind of gas mileage do you get with your 67-72?
15-17mpg driving from modesto to san mateo daily (180 miles round trip). 350 motor with 375hp and 700r4 with 3.07 gear rear end.
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Brian XNGH ECV Chapter 58 1972 Jimmy / Blazer Project 2wd 1974 Chevy Crew Cab Shorty |
08-17-2020, 04:04 AM | #77 |
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Re: What kind of gas mileage do you get with your 67-72?
[QUOTE=68Blu;8792826]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?[/QUOTE
That really depends on how you are driving it. Spirited driving that’s good. Driving for mpg on the highway that’s a lil disappointing. Hwy mpg < 65 you should be able to attain 16 or better if it’s dialed in and cam timing is not too wild. Just my 2 cents.
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1967 C10 Suburban 454/TH400/3.07's An Average Joe and His 'Burb: http://67-72chevytrucks.com/vboard/s...d.php?t=775843 |
08-17-2020, 11:05 PM | #78 |
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Location: California Central Coast
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Re: What kind of gas mileage do you get with your 67-72?
Well, looks like she’s getting about the average. Put her on the dyno this weekend and everything is functioning as it should. Looks like I’ll have to suck it up but was really hoping 13-15 mpg.
Steeveedee, no camper shell or wife. Does a husband count? 53 gallon tanks I’d hate to have to fill that up |
08-17-2020, 11:38 PM | #79 | |
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Re: What kind of gas mileage do you get with your 67-72?
Quote:
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~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA |
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08-21-2020, 12:45 PM | #80 |
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Location: TOULOUSE, FRANCE
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Re: What kind of gas mileage do you get with your 67-72?
1972 c20 cheyenne stock 350 4bbl with rebuilt quadrajet and recent tune up, TH350 and 9.5x16.5 tires.
Stock rear end I guess. City, short trips: 10mpg Highway/country road at 55mph: 13mpg. It seams to be average figures for a stock truck. |
08-21-2020, 01:18 PM | #81 |
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Re: What kind of gas mileage do you get with your 67-72?
Over the last 9549 miles I have averaged 11.6 with a best of 16.3 and worst of 7.2 This includes the stock 350 and now a GM 350 performance crate motor, the th350 trans and now a 4 speed OD. I have 4.10 gears and 31.5" tires. Yes I log every fill up.
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Terry 1970 Custom Camper/C20 , GM Crate 350/7004R, Dana 60, factory AC |
08-22-2020, 05:08 AM | #82 | |
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Re: What kind of gas mileage do you get with your 67-72?
Quote:
That’s a true average. I keep a log book in mine and chart every tank as well. Kind of a necessity as my fuel gauge is and has been broke for the last 10 years. Lol.
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1967 C10 Suburban 454/TH400/3.07's An Average Joe and His 'Burb: http://67-72chevytrucks.com/vboard/s...d.php?t=775843 |
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08-22-2020, 07:37 AM | #83 |
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Re: What kind of gas mileage do you get with your 67-72?
13mpg at best
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08-22-2020, 08:27 AM | #84 |
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Re: What kind of gas mileage do you get with your 67-72?
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08-22-2020, 10:24 AM | #85 |
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Location: Vacaville CA
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Re: What kind of gas mileage do you get with your 67-72?
This is a frustrating topic for me! I had read the many posts from people getting 15-17 mpg and that was the range I wanted to be in so I could daily drive my 72 fleetside longbed.
I bought a new Blueprint Engines 383, 430 h.p. and had an early 700r4 non-electronic lock-up rebuilt and upgraded. I have 18's and haven't verified but it should be the original 3.07 gearing. Got everything installed with FITech supplying the fuel and started putting on some miles. First oil change was at just over 600 miles and I've been logging every tank. Mostly around town with some country driving at 60-65 and I was getting just over 7 mpg! Very disappointing to say the least on mileage but wow is it fun to drive! Smooth, great acceleration, sounds great, no issues with performance. I purchased a complete MSD ignition system (distro, 6AL, coil) and had an X pipe installed and starting using Drive instead of OD in town. Now I am just over 9 mpg and I did a couple freeway trips at just over 12 mpg. I don't know of anything else to do to get the mileage up. Don't get me wrong, the truck runs fantastic and it is amazing on the freeway now. With the tired 307 and no OD it was screaming loud at 65 now at 85 it is quiet and just cruises along comfortably. I've never driven an LS motor so I don't know if I would have been as happy with that option but I'm sure it would have given better gas mileage? |
08-22-2020, 11:24 AM | #86 |
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Re: What kind of gas mileage do you get with your 67-72?
As good looking as these trucks are. They still have the aerodynamics of a brick.
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"Some Days Chickens And Some Days Feathers" Dale XNGH ECV Sam Brannan 1004 R.I.P. 67ChevyRedneck R.I.P. Grumpy Old Man |
08-24-2020, 05:04 PM | #87 |
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Location: Southern Oregon
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Re: What kind of gas mileage do you get with your 67-72?
[QUOTE=Lancialonnie;8796188]This is a frustrating topic for me! I had read the many posts from people getting 15-17 mpg and that was the range I wanted to be in so I could daily drive my 72 fleetside longbed.
I bought a new Blueprint Engines 383, 430 h.p. and had an early 700r4 non-electronic lock-up rebuilt and upgraded. I have 18's and haven't verified but it should be the original 3.07 gearing. Got everything installed with FITech supplying the fuel and started putting on some miles. First oil change was at just over 600 miles and I've been logging every tank. Mostly around town with some country driving at 60-65 and I was getting just over 7 mpg! Very disappointing to say the least on mileage but wow is it fun to drive! Smooth, great acceleration, sounds great, no issues with performance. I purchased a complete MSD ignition system (distro, 6AL, coil) and had an X pipe installed and starting using Drive instead of OD in town. Now I am just over 9 mpg and I did a couple freeway trips at just over 12 mpg. I don't know of anything else to do to get the mileage up. You are on the right track. Keep tinkering and logging every fill up. The people that are getting 14 plus mpg hwy have put a lot of effort into achieving that number or are using creative math. Your 383 is pretty wild in terms of gas mileage being the optimum goal. Typically better mpg is achieved with milder cam timing. IE less duration and lift. Compression is efficiency but staying out of detonation with a smaller cam and higher CR’s is much more challenging. In other words, it’s tough to have your cake and eat it too.
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1967 C10 Suburban 454/TH400/3.07's An Average Joe and His 'Burb: http://67-72chevytrucks.com/vboard/s...d.php?t=775843 |
08-24-2020, 05:31 PM | #88 |
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Location: Central Coast Ca.
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Re: What kind of gas mileage do you get with your 67-72?
1971 C10 with 250 and 4 speed trans with original single barrel carb and points ignition. The only time I checked it worked out to 14.5 MPG when doing mostly shortish trips.
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08-24-2020, 05:59 PM | #89 |
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Re: What kind of gas mileage do you get with your 67-72?
WOW! This is great, i am doing the same set up with a 2004 6.0 lq9. Same rear end ,same transmission. I have a set of 16.5 inch slots That i hope to run with 33” tires with.Did you do a build thread by any chance?
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08-24-2020, 07:12 PM | #90 |
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Re: What kind of gas mileage do you get with your 67-72?
The 67 with all the bells and whistles plus a 327 and glide that I had in Texas in the 70's got probably ten on the road if that. It was the worst gas hog I have ever owned.
The 70 longbed with 4 speed and 3.73 gears with a 307, power pack heads, Z28 Cam. 300hp 327 intake and Holley spread bore got 16 on a road trip to Texas. My 71 3/4 ton got about 14 on the road running back and forth to work going 23 miles each way every day. Far less on short runs to town and back.
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Founding member of the too many projects, too little time and money club. My ongoing truck projects: 48 Chev 3100 that will run a 292 Six. 71 GMC 2500 that is getting a Cad 500 transplant. 77 C 30 dualie, 454, 4 speed with a 10 foot flatbed and hoist. It does the heavy work and hauls the projects around. |
08-24-2020, 07:24 PM | #91 | |
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Re: What kind of gas mileage do you get with your 67-72?
Quote:
My brother bought a brand spank'n new 74 Stepside with a 454 it only got 8 mpg pulling his ski boat or not. One time he bought this real expensive aircraft wax which was supposed to make it slicker.....with no boat...still 8 mpg! |
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08-24-2020, 09:52 PM | #92 |
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Location: Simi Valley, CA
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Re: What kind of gas mileage do you get with your 67-72?
Gonna drive that truck 180 MPH to get back that .5 MPG he wants? What's true for planes is a long way from true for trucks, as I'm sure you know.
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~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA |
08-24-2020, 11:05 PM | #93 |
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Re: What kind of gas mileage do you get with your 67-72?
Fun stuff here, gotta add another two cents. Last year my 72 GMC 2500 got about 8 mpg with a tired 350, 350thm and a stump puller rear end.
Since then I've added headers, dual exhaust, FiTech EFI, electronic ignition, and a fresh 700r4. Same tired 350 and rear end, now I'm up to 11mpg. I guess I'm not gonna brag about 11, it's more fun to say that it increased 37%! And hey, if I drive it 145 more years, the better has mileage will pay for the upgrades! Guess I'll still be a regular at the gas station. Jim |
08-25-2020, 03:46 AM | #94 | |
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Re: What kind of gas mileage do you get with your 67-72?
Quote:
My truck came with a straight 6 and 4:11 rear, and that poor little engine did scream at 65! Swapped in 350/350 and a 3:07 rear and maybe I'm just comparing the two but it doesn't seem to scream at 65 to me anymore. For the cost and the peace of mind, I would pull that cover just to verify the gear ratio. 430 horse 383? Never considered that as an econo motor, even with EFI and OD, but 12 highway doesn't sound too bad IMHO. |
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08-25-2020, 09:21 AM | #95 |
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Re: What kind of gas mileage do you get with your 67-72?
My 68 with 250 i6 granny 4spd 4:57 rear about 9 mpg round town or highway but then again highway was doing 50 mph . Engine is really winding out
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Mark 72 c20 custom camper Husky edition, 66 SS396 Chevelle 1964 Hawk, 63 Avanti,62 lark 1969 AMX , 1968 c20 stepside ,85 K20 1977 Suburban sold 68 anniversary. |
08-25-2020, 10:01 AM | #96 |
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Re: What kind of gas mileage do you get with your 67-72?
Just drove 950 miles at 70-75 mph and got right at 16 mpg. This is a '71 C20 with 383, Quadrajet, HEI, 4L80E, 4.10 gears, 235/85R16.
My TPS showed about 27-32%, so clearly this is not the most aerodynamic vehicle. I still have some tuning to do on the carb, might get another mpg out of it, but I think I'm close to the best it will ever do at interstate speeds.
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1971 C20 Custom Deluxe, HT383, 4L80E, 3.73 Locker, 4 Wheel Discs |
08-25-2020, 10:05 AM | #97 |
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Re: What kind of gas mileage do you get with your 67-72?
I may win the mileage war. 20+MPG but I cheated. My truck is Cummins re-powered with a 5spd manual with OD.
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1972 Cheyenne Super 20 Custom Camper 12 Valve Cummins/5spd manual 1972 Cheyenne Super Short Bed 557 Med Olive DK olive 1970 K5 Blazer Dark Gold 1966 Coronet 440 35k mile survivor 1991 Suburban 2500 454/4L80E 2wd 1985 Monte Carlo SS 383 Sbc, t-56 magnum 6spd and Ford 9" |
08-25-2020, 12:57 PM | #98 |
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Re: What kind of gas mileage do you get with your 67-72?
I have an 07 5.3 with a 4L60E in my 72 short bed. On the highway I get between 19-20 a gallon. In town I get around 15-16.
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08-25-2020, 07:03 PM | #99 |
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Re: What kind of gas mileage do you get with your 67-72?
Cheater. Greater energy density in a gallon of Diesel oil than gasoline. Plus 5 speeds. Where is the ref? Kidding! I do like your truck. I'd drive it...
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1971 C20 Custom Deluxe, HT383, 4L80E, 3.73 Locker, 4 Wheel Discs |
08-25-2020, 10:17 PM | #100 | |
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Re: What kind of gas mileage do you get with your 67-72?
Quote:
I have 20" wheels on it all around.
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1971 LWB Custom, 6.0LS & 4L80E, Speedhut.com GPS speedometer & gauges with A/C. 20" Boss 338's Grey wheels 4 wheel disc brakes. My Driver Seeing the USA in a 71 Upstate SC GM Truck Club 2013,14 and 2016 Hot Rod Pour Tour http://upstategmtrucks.com/ Get out and drive the truck this summer and have some fun! It sucks not being able to hear! LWB trucks rule, if you don't think so measure your SWB! After talking to tech support at Air Lift I have found out that the kit I need is 60811. Per the measurements I gave them. Ride height of truck inside spring and inside diameter of springs. |
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