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El Camino Gas Mileage

6K views 7 replies 5 participants last post by  bisjoe 
#1 · (Edited)
I use my '72 El Camino 350 330HP/TH350 daily to commute and
as a shop truck for my business (1000+ miles/mo). With reg.
gas at $2.79 here now and getting 12-13 mpg, am
considering trade or sell/buy for more economy.
It runs OK on regular but really should be drinking at
least 92 octane (over $3). I love the muscle but I don't
see the gas prices dropping in the near future and don't
want to let her sit in the driveway. Have gotten as much
as 20 on along drive cruising at 70 but normal for here is
bumper-to-bumper, 25-35 with lots of stops at 12mpg,
and some good freeway driving 13.x. Keep it well tuned,
tire pressure etc., and tried driving like an old lady, no
difference. Please respond if you have an El Camino with
327, 283, or 6 cylinder, and let me know the gas mileage
you get and which transmission you have.
 
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#2 ·
My info is dated since I don't drive it ('65 EC) anymore, and rarely in the 80's, but back in the 60's/70's I used to figure 15 mpg average and that was a little conservative. Usually around 20 mpg at 70 mph level no-wind. 327, 250 hp, 4-spd 3.08 gear. Rochester 4GC. Points w/60's kit CD ignition. After no-lead gas came in, I had to be real careful with the throttle to avoid "pinging", but I ran it on regular no-lead with the 10.5 cr.

When considering spending money to get better fuel economy, you'll have to take a close look at the payback/break-even time.
 
#3 ·
Thanks for the info.

I did some calculations, if I get 20mpg on a vehicle that runs
well on 87 octane I'll save $61 from using 87 on this one,
which pings going slow up a hill, not good for it.
If I compare it to the price of using the 92 octane that it
needs, I'd save $87/mo. I'm a little surprised it's not more,
but if the prices keep going up so will that difference.
I learned to drive in my grandmother's (new then)
'64 Chevelle 283/PG and it got 20-22.
 
#4 ·
bisjoe said:
Thanks for the info.

I did some calculations, if I get 20mpg on a vehicle that runs
well on 87 octane I'll save $61 from using 87 on this one,
which pings going slow up a hill, not good for it.
May or may not be a good idea... but you might be able to tune around that ping by changing the vacuum advance setup. Use an adjustable vacuum advance can to raise the vacuum setpoint where advance is pulled out.

Part of the game is operating closer to the edge with less safety margin. For example most efficient cruise is at about 14.7 AFR. But if you tune for that at cruise you may go too lean with other conditions, like going up a hill. This can kill driveability and/or engine parts. So most carb setups leave some economy on the table in favor of safe conservative operation.

And it is why EFI provides better fuel economy (constant feedback and self-adjustment).

It always is a bit surprising how hard it is to make a cost/payback analysis work out positive on fuel economy.
 
#5 ·
no advantage to change vehicles based on gas mileage unless replacement is free to you, same insurance and parts \ labor are cheaper. newer vehicles tend to cost more to repair. Your mileage on a 1972 which I own three of, including a BBC, all with automatics and low 3 series gears get 12-17 in town and 20 on the hwy. use 87 octane, it was designed to not knock. change timing, dual exhaust and headers help, radial 14-15 in tires, bigger gives more rolling resistance and changes rear ratios.
 
#6 ·
The best thing I have done for my El camino has been lowering the tailgate before I drive on the highway. Simple, and you will see an improvement.
The other thing I do when I worried about gas mileage is make sure my car is in a good state of tune. Clean air cleaner. And put on a vacuum secondary holley insted of the double pumper. And when your car requires better fuel you're ahead by running the right octane. Might not be cheaper but you'll use less and you'll be ahead because of increased efficiency.
Just what I've observed. I may be full of you know what but not on purpose. Just trying to help, the price of gas is really ****ing me off. Please excuse the French. Later.
P.S. I almost forgot the simplest of all- your tire pressure! Run it on the high side of the recommended pressure. That and the tailgate are the most noticeable. IMHO
 
#7 ·
I almost forgot to say that the other day I was thinking about the old gas crunch 73' or 74'. Remember all the people who sold their precious muscle cars cheap? And how they kick themselves in the ass now? Maybe this is the same type of situation. I'm not getting rid of mine. It'll go back down ( the price of gas). Never as low as it was now that the oil companies know more than ever how they got us. The gov. should keep this from happening somehow but what do I know. Sorry I'm windy today.
 
#8 ·
Thanks for the replies. I do keep it in tune, a couple of extra lbs in the tires, and have a tonneau cover on it. I remember sleeping in the car in line for gas
in '74, I also remember filling my (new then) '73 Ford Courier for $4. I have heard two theories on gas prices, one is that it will drop in a month or so to
$2.60+- and stay between there and $3. The other is that by 2007 we will all
long for the days when it was "only" $3. Who knows? The bottom line for me
is that when I got the '72 I also considered a '64, and still like them, so if I
do find an opportunity to trade, or maybe sell the '72 and buy a '64, I'll do it
and go for a more efficient engine. I can always upgrade that for more power
if gas goes down or I no longer need to drive as much, but downgrading this one for less power would be a shame. I just don't want to own a classic that sits in the driveway. Have been driving my Explorer "snow car" all week, by now would have had to fill up the EC, but am only down 1/4 tank.
 
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