The Stovebolt Site Forums The Shop Area General Truck Talk best possible gas mileage

With gas prices now reaching $3.50/gal.(thanks Mr. President)I'm searching for ways to make my '63 C-10 as fuel efficent as possible. The engine is a 250 six that was pulled from a 1970 Nova by the previous owner. It has a single barrel carb. So far I've switched the points to a Pertronix set up, had the carb rebuilt(but it's still leaking). I plan to switch out the old exhaust manifold with a set of Headman headers. They claim it will increase gas mileage up to 10%. Can anyone give me some advise as to extracting the best possible gas mileage out of this engine?

use an air cleaner that will draw air 360 degrees,not through a snorkel type if the motor has EGR,disconnect the vacum hole and plug it off.

Consider an overdrive transmission or a taller - lower numeric - differential ratio.

lift your foot off the gas pedal, time your approach to lights, limit your RPM's.

my gas mileage varies from 14 with my lead foot, to 16 when i pay attention during my daily 40 mile (RT) commute.

Here is a link to another site that talks about several different engine, tranny, and rear end combos as well as mileage. It mostly talks about 700r4 tranny, engine combos.

http://www.chevytalk.org/fusionbb/showtopic.php?tid/177561/

1. Take it easy when accelating from a standstill, and if you have a manual transmission, downshift when approaching traffic lights. It will help save your brakes too.

2. Make sure you push the choke knob in all the way once the engine has warmed up.

3. Make sure your tires are not low on air. I inflate mine to 35 psi.

4. Check for any air leaks in your intake manifold. I experienced the problem frequently with the inline 6.

I was able to get around 17-18 mpg on the highway with a 250 and a 3 on the tree in a 1966 C-10, and it was original. I get about the same with my current 1966 C-10 with a 283 and a Powerglide transmission.

Andy;
In addition to all the good suggestions above, also check your vaccuum and centrifical advance.

I'm tempted to ask what "Mr. President" has to do with $3.50/gal gas but this ain't the place for political commentary.

i am not an expert by any means on this stuff but, from past experience chevy straight 6 bangers love gasoline. with gas as you said at 3.50 a gallon i have driven and still do drive more fuel efficient V6 hooked to a 5 speed out of a S10 truck. my little s10 truck got mid 20 mpg's all day long. my dailey driver now is a 4 cylinder S10 and it gets low 30 mpg's. chevy's new power plants with the fuel injection seems to help in the fule mileage area. i know big ole real trucks have big motors...but ole real trucks also suck gas bad....maybe it's time to rethink the whole engine thing again...
thanks for listening

You can probably advance your ignition timing a small amount from stock before it pings. That will help as well. Other than that, tall skinny tires, overdrive, gear changes, and maybe better streamlining. Keep it right at the speed limit. You might experiment with leaving the gate down. Some trucks it makes it better, some worse. A tonneau cover might be even better.

how about a cam from patrick's?

Here again I am definitly not an expert.I have found however that gearing seems to mean everything as far as MPG is concerned,and yes you need a well tuned engine to drive those gears.In my 55 2nd I have a rebuilt 350 Chevy truck engine,(circa 1974)plus a 700R4 trans.going to the stock 3:90 rear.It gets me 20 MPG all day long as long as I drive it carefully.This includes city as well as highway miles.The OD trans.seems to be the secret to better mileage,however you have to have enough power to push the vehicle.A 3 speed auto,or a 3 or 4 speed manual trans will turn 1 to 1 to the rear,whereas an OD trans will go at about .78 to 1 final drive.You should be able to use a regular manual,or 3 sp.auto.and use a rearend geared about 3.08 and get decent mileage as well.It all boils down to how many RPMS you are turning at cruising speed.My findings are strictly on a trial and error basis.

How nice it must be to be paying $3.50/gal - that works out about £1.80

Over here in Scotland we are now paying £5.00($10.00) a gallon). I'd still rather have the old truck than a modern diesel one though...

I'm no transmission expert so I'm assuming that I could just replace the ring an pinion inside the caseing? Or do I have to find a used differential with the ratio that would give me better mileage?

Andy,I am no expert either. But if you can obtain the correct ring and pinion for your present rearend,that should work.I have no idea what rearend you are using,and whats available for it.A lot of times it is easier and cheaper,to get another complete rearend from a wrecking yard.

$10.00/gal.!!! I had no idea gas was that expensive anywhere in the world! That just goes to show you how secular we Americans can be. At those prices I take it your '41 3/4 ton Chevy is not your primary source of transportation?

Yeah, but gallons come with an extra quart in Scotland. They also have much shorter distances to drive than we do.

It's not my main form of transport, petrol costs and the salt on the roads in the winter would make that difficult.

A UK gallon is 1.2* a US gallon - I'd love it to be 1.2 the price

Its the tax that makes it so expensive - approx 80% goes of the gallon price goes in tax.

We don't have to pay any road tax (£210 per year) on classic cars so I save that way.

Driving an old truck is worth the extra though - I'd rather drive half the time in something with sole.

if you are looking for a ring and pinion set check out randy's

http://www.ringpinion.com/

They should be able to get you everything you need, plus they also have calculators so you can figure out what rpm you will turn at a given speed.