HMMMMM the six cylinder's may have some use !

[67chevy1series]

Originally Posted by thankins93

am i looking at around like 10-12 then?

that sounds close

[helldiablo]

Originally Posted by y5mgisi

helldiablo
First, 20mpg is impressive no matter what. i would like to know the specs on your car cause 25mpg seems a bit far fetched coming from someone who is not impressed by a 20mpg truck. Try doing the same thing you did to get your mpg but do it from full tank to empty tank. Then do it a few more times and average that out. If all you do is exclusive highway milage, thats going to boost your numbers alot! My bet is your total combined MPG would be alot more like 15mpg.

y5mgisi,
i didant mean to hurt your feelings man 20mpg is cool i never said i wasent impressed awsome dude 20mpg **** YEAH!!,

the specs on my car are as follows... 350 4 bolt main bored .60 over, .20 under on the rods and mains, H beam rods, plasma rings, 270 roller comp cam, keith black pistons, 202 heads ported and polished, 3 angle valve job, hardend stainless valve seats, holley street dominator single plane intake,a q-jet from a 74' 454 truck, stock exaust manifolds to 2.5 in 40series flowmasters, The transmission is a th350 with a mild shift kit, ported and polished valve body, 2000rpm stall converter. 2.72posi rearend gears tire size 205/70/15.. any other questions i can look in my build sheet.. the motor was built 10years ago by doug timmons and is my daily driver. here are some crapy pics of the motor.

ive had this job for 3 years now and a tank of gas last me the whole 5day week i have a 12 gallon tank... (good enough average for me no?) yes i agree they are a majority of freeway miles,

but i guess i could still be to ignorant to do basic Arithmetic (awww now im sad)i guess i should go back to school huh? ...
any who, have a superfantastic day and enjoy your chevys regardless for fuel milage,,, Ivan(helldiablo)

[pat 70/71]

Ivan, I also have a 65 nova coupe. zz4/hot cam 750 dbl pumper msd hei b&m 350 trans best it has done is 15 mpg and that is ok by me. you should check out Steves nova site I'm on that site all the time just like this site lots of great people! come check it out ! cheers, Pat

[basemodel67]

I have been thinking about the new 4.2L straight 6 out of the Trailblazer/Envoy - 290+ HP, FI, DOHC, and all aluminum! Now I just need to find a short-stepper to put it in.

[68gmsee]

Originally Posted by basemodel67

I have been thinking about the new 4.2L straight 6 out of the Trailblazer/Envoy - 290+ HP, FI, DOHC, and all aluminum! Now I just need to find a short-stepper to put it in.

Sounds good but I wonder if it would be economically feasable. A Trailblazer doesn't get much better than 20 mpg (mine averages about 19) on the highway and if one can get 20 out of a 250 six with a rear end change and maybe a transmission swap that may be the way to go.

[68gmsee]

Originally Posted by helldiablo

..........i figured with basic math skills that 50.3miles divided by 2gallons equals 25mpg(roughly)....... ,,, Ivan(helldiablo)

Sometimes in a man's life all the stars line up and you get the perfect match of engine, tranny and rear end in an automobile. Back in the early 60's my brother had a beat up pontiac with a manual tranmission. Looked like cr@p on the outside but ran like a scalded ape. The engine had been blue printed by a south Texas 50's hot rodder and was unbeatable with the locals on the country strip. It became sort of a legend and every young hot rodder wanted be the one to beat him.

Sadly, he flipped the car after a tire blew out in one of his many challenges. I bought the engine installed it in a 55 chevy 2 door sedan with the same pontiac transmission and 3 deuce manifold. Never ran the same.

So, hold on to this one and don't make any changes. Just a swap here and there may screw it up.

[Dark Knight]

Best I ever got with my six, 3.08 gears and 3-speed was 12.3 MPG. I just popped in a 355 and my mileage went to somewhere around 9-10. I haven't filled up yet, so I don't know. Of course I was hammering on the secondaries as well trying to get the darn thing tuned right. I'll bet that made matters worse. And I was burning out all the time to show off to my buddies. Especially the one who drives the POS Toyota Tacoma and thinks his truck is better than everyone else's. Next on the list: NV4500 and Cliff Ruggles book so I can mod the Q-Jet a little.

[406 Q-ship]

I just did a quick mileage check on my 67 C10 stepper with a 350/th350 probably has 3.08 gears (I have not confirmed the ratio). Believe it or not it got 17-18 MPG average split between highway and city driving. Not too bad for a V8 truck without an overdrive.

[el_bole]

I was going to replace my straight six 235 for a 350 and decided to keep orig. engine due to too much dinero $$$ to do swap and man Im glad it worked out that way!!! Way keeper to cruise than a V8 especially in Sunny SoCal....

[el_bole]

Oh by way its a four speed manual trans lol....better mpg...

[el_bole]

I just traded a rifle for a 283 from a 68' camero.....again my 61' has a 235 straight six in it now with a four speed tranny. Do any of you know what parts I'll need to do the swap? I already researched eng. swap plates from Trans Dapt but need guidence as to where to to install on my truck.....Any info would be greatly appreciated. Thanks fellas...

[truckster]

Originally Posted by helldiablo

WOW only 20 mpg out of a 6 banger?.. my nova with a mild 350 4bbl gets that easy, if not better, and i can shred the tires off the rims........... how do you guys get your milage numbers?.... i got mine by this method....(distance traveled divided by gallons used) my work is exactly 50.3 miles round trip, (the gas station is litterally 2 blocks away from my house). i filled up and went to work on the way home i filled up again at the same station, same pump. i was only able to cram 2 gallons into the tank before full again. so i figured with basic math skills that 50.3miles divided by 2gallons equals 25mpg(roughly)..

You can't really get a good read on your gas mileage with just two gallons of gas, unless you're doing it under very controlled circumstances. Although it's great if you're really getting 25 mpg, the only way to tell for sure is to keep a log and record the mileage and fuel use over several fill-ups. That will average out a lot of the variables that can have a huge effect on a short test, such as fuel temperature and even how you put the nozzle in the tank when you fill it.

[Husker]

Originally Posted by 19673ontree

with gas going up my 67 six cylinder is more appealing to ride around town , with a 3.08 rear mine get's just over 20 mpg ,,

What transmission you have? I was thinking of putting 308's in mine with a 3 speed on the tree.
Ron

[bosco200]

My 250 is a gas hog....4.57s might be the problem

[mr48chev]

Originally Posted by truckster

You can't really get a good read on your gas mileage with just two gallons of gas, unless you're doing it under very controlled circumstances. Although it's great if you're really getting 25 mpg, the only way to tell for sure is to keep a log and record the mileage and fuel use over several fill-ups. That will average out a lot of the variables that can have a huge effect on a short test, such as fuel temperature and even how you put the nozzle in the tank when you fill it.

Several fill ups at the same pump too. Different pumps even at the same station can shut off at much different fill levels.

The best gas mileage I've had with one of these trucks was 16 on a road trip from Washington to Texas running a 307 with a 4 speed and 3.73 gears. The six it replaced probably got 11 or 12 but I think it went through a half quart of oil per gallon of gas. Just because a truck has a six doesn't mean it will get respectable gas mileage.