just went on a trip to athens and back ,a load of wood ,two 270 pound guys and running 70-15 mpg not to bad .tires are 235/75/15s

Less than 7 mpg. When I built it gas was like 1.00 per gal and that wasn't so bad. Then it went to 2.00 per gal and I cut back on driving it. Now at 3.30 per gal I just drive it to the car shows. :rolleyes:

I clicked 10-12 but I may have moved back to the 7-9 category.

I have data on every drop of gas I bought since I got the truck in 1994.

When I got it I got around 7mpg.
A valve job, new cam, and general tune-up got me to 10 towing my boat, 13 without towing.

My best was 13.42 mpg, worst 3.91 mpg.

That was with a 3-speed manual behind a 350 of questionable origin, in front of a NP205. 3.73 rear end gears.

Then I switched to a th350 and NP205. My mileage slipped to 9.43 but I have winter to factor into the whole thing.

In the winter I only drive the truck on the lake, thus keeping it off the salty Minnesota roads. I fill it fuller than a tick in November, get on the lake through my back yard, drive it about 1/4 to 1 mile at slow speed in 4wd. These tank fulls generally run 3-6 miles per gallon so that throws everything off over all. (I have the 20 gallon seat tank and 17 gallon aux tank so I usually make it all winter).

Because of recent rises in gas prices my last fill up was June but I'm getting pretty low so I'll get another data point soon.

I only have approximately 500 miles on my new 383 with new Edelbrock 4bbl which replaced my 350 and stock 2bbl. Once again everything is different. The few fill ups I have since then are inconclusive.

I went 18 to 20. With the 230 I6 and a one barrel carb, I ain't no speed demon, but that's ok, my brakes are to bad to go very fast.

I get right at 10 in town driving and around 14 on the hiway. In the '71 that is. The Blazer still gets nothing, as its never been driven :whine:

I've never seen anyone install such asmall engine in there truck...did you do that specificly for the MPG? And what gear you have in the rear?

I am getting around 12 mpg in both the '86 and '70. I think I might be getting closer to 13 in the '70. Don't you just hate it when you can watch the gas gage needel move? You look at it and look away and then look at it again and it has moves a little. Not good!!! :(

I get around 9 mpg in the 69, its got a 454 with a lumpy cam and the big oval port heads as my neighbor told me one time about his old camaro, it can pass anything but a gas station.

72 GMC C-30 Dually. 8 miles to the gallon 305 V-8 sbc with four speed on the floor. I have never checked but have been told I have 4.54 rear. has a 157" wheel base. The one thing I do know is the truck has managed to pull a heavy equipment trailer with a 6 ton dozer about 10 miles. Didn't go very fast, but it did it. Also I run about 4000-5000 RPM at 65 mph. Its a work truck meant to haul heavy loads what should I expect! Now I realize I do not need something this heavy duty so I'm looking at selling it.

I clicked 10-12mpg. The new engine isn't broken in yet HT502/TH400/4.11 rear. The old 402 got 10.5-14mpg with the same drive train. When I pull the camper it is about 7mpg.

Hound, I have a 4.10 and whole pumpkin in an eaton diff here for sale...

I voted less than 7 and up to 9. I might be getting better mileage but that's only on the highway. My truck doesn't see much highway driving though. Most of the time I drive it to school, around town, and on the farm roads, that's about it. I did drive it out of town one time, I got about 12 or 13 MPG when I drove it to Seguin(by San Antonio). It was about 180 miles total. I had just put some 33-12.5-16.5 tires on it, looking for some 35's now. :metal: The engine's been running weird lately, guess it needs a new dist. cap and the points adjusted.

My bone stock 307 averaged 9.5 on a cross country trip, California to Maryland. Believe it or not, she was well tuned and running great at the time.

believe it or not i get between 12 & 13 IN TOWN!!! I have the timing & fuel curve on the ragged edge of fatal detonation. but what the he!!? it gets good mileage & if I drive careful it doesnt ping. not to mention how the torque is cool.

now, my daily driver/rider, it gets 60 MPG on the highway. so what if its a rice rocket? it can go from 0 to pver 50 MPH in one block!

in short, BITE ME oil man!!!!!!!!!!

My 71 has been parked for a few years now but when it was a daily driver it was 15-16 average if I kept my foot out of it and 18-20 highway (yes, I did get 20 mpg once traveling 50/55 following a friend towing a trailer from CT to PA). Pre-700R4 it was 13-15 no matter what.

I put 13 to 14. I would have put 15 to 17 if I could drive like a normal person. I just seem to have a problem with a heavy foot.

GMGoodwrench 350/TH350, Edelbrock Performer intake, Holley 570 Street Avenger, HEI dizzy, 3.73 gear.

Never really checked mine in the blazer but I fill it up every 2 weeks on paydays and it will last me even if I am putting my foot throught the fire wall or driving it like miss dasiy..

And give up the ability to smoke dual wheels? Like I said I'm hoping to sell it. If I can't sell it we will see, but I did some checking of wieght and scrap Iron prices and this truck is worth almost $500 in scrap alone. I hope it doesn't come to that, but the wife doesn't like it and I really do not need to pay to register a truck this big when I'll never use it all. I work on 68-72 Nova's now and lets just face it my little F#rd 150 can handle a car this light. So the reality of it all comes to the for front. On Wednesday it will be listed in the local Penny Saver. Had alot of luck getting rid of parts that way we will see what happens with a whole truck!!

4.56 gears, 350 four barrel and no overdrive......can we say single digits...

Yes you may. :(

Wow..I remember you sayin that the train of trucks coming up from cinci was slow, but I didn't realize you had 4.56 gears in that sucker. WOW.

Voted <7, almost nothing but short x-town trips anymore & I gave up checking mpg years ago - just pour fuel in as required... :rolleyes:

I know where Seguin is my dad grew up there what did you do down there?

first engine 350 with Holley Multiport EFI & mild Crower roller, 750R4 AND 3.73 gears got an average of 20+mpg, my recent 413SBC 10.2 cr, Vic JR Intake, 650CFm Mighty Demon, ProtopLine 220cc Heads w/2.02/160 valves, Crower 286/292 562/567 lift Roller, 4.10 gears and 700R4 average was around 12, could possibly hit 15 if I could keep the foot out of it (busted a piston), new motor all forged 420CI SBC, 10.5 cr, Vic Jr heads w/2.08/160 Valves, Motown Single Plane Intake, 750 Mighty Demon, same wild Crower roller cam, trans & rear. ???

My MPG
 

I voted 10-12. 68 Chevy Step Side mild 350 with 650 carb 3.73 rear and lil 275/50's out back