Anybody have the gas saver indicator that is working?

Are you talking about one of the old Motor Minder vacuum gauges?
If so I do have one and it is not for sale or loan.

I'm thinking he is referring to an indicator light that was on certain cars of the late seventies. Been a long time since I was behind the wheel of one so equipped. The modern day equivalent, on my 2014 hemi express, is now an ECO light.

Wasn't that the deal that lit up the turn signal light on top of the left fender when you got happy on the gas pedal?

God, I had so forgotten about that!

Yes, it lit up the left fender mounted turn signal when vacuum went down. I was looking through my 75 service manual, and came across it. I think my dart might have it, but I'm not sure. Just wondering if anybody had one that actually worked, and what the components looked like.

My '77 Volaré came with that and it worked fine. Scared me at first because I didn't know what it was, lol! If you google "Fuel Pacer" you'll find more info. It's basically just a vacuum activated switch that turns on the fender lights.

I had a 1975 Duster that had it....

I plan on using mine someday on my 57 Plymouth.....just have to get through the instructions

Interesting devices.

The Brake Specific Fuel Consumption,
or BSFC maps (graphs) have long shown that
there is an "island" of good fuel economy
rising out of a "sea" of poorer fuel consumption.

The horizontal ( East West)
direction of a BSFC map
is almost always RPM,
but sometimes is average piston speed ( more "universal" because engines have different crankshaft strokes)

The vertical ( North South)
direction of such a fuel economy map
can be many measurements such as
Torque, manifold vacuum, throttle position,
or the more "universal" BMEP: brake mean effective pressure.

If Chrysler only put a single light out on top the driver's side fender
indicating a level of manifold vacuum,
didn't this only do half the required job?

To be most effective,
there should have been a second light, or second colored light bulb inside the same glass,
to indicate the driver was also inside the correct RPM range,
which is set by selecting the best gear for that road speed.

Ideally inside the vehicle owners manual
there would have been a
big bold colored graph
showing manifold vacuum on the vertical axis and
RPM on the horizontal axis.

Think this would have been too complicated for typical car owners?
Maybe.

But i bet you that if correct understanding of these lights and graph had been an extra credit item on the driver's license exam, many sixteen year olds ( 14 in Mississippi) would have ace'd it.

Today's teenagers do not seem to be highly motivated about driving, much less understanding automobile technology, but spend hundreds of hours honing video game knowledge.

The light(s) out on the fender are a "public display" that other drivers can see.

Hmm,
that is a new angle,
I had not considered.

What would be my reaction if
another driver in the same make and model vehicle passed me on the Interstate
but as he went by i could see two lights on top his fender indicating from both that he was driving inside the "island of best fuel economy"
whereas my lights showed my vehicle was not?

Aero mods, gear ratio changes, engine mods, low rolling resistance tires, could all honestly cause this.

Obviously, it could be dishonestly "hacked"

Actually, I think fender mounted turn signals were for people to lazy to look down at the panel. You do get used to them. But you're right about all of the other stuff. Read what Charles Lindbergh did to save gas for P-38 pilots in the Pacific theater.

Good read... Allowed the P38's to accompany the bombers all he way in and out...

I guess today an $20 Arduino, $10 vaccum sensor and some $5 LED lights could create a Gas Saver front fender light display. I am guessing the Arduino can count electronic speedometer pulses and get RPM from fuel injector pulses. Maybe it could also turn on water injection into the throttle body at some vacuum level like an old Spearco unit.

It's called the "Fuel Pacer" and lots of Mopars had them well into the 80's. I've seen minivans with a green LED labelled "Fuel Pacer" in the fuel gauge.
I had a Valiant Brougham with it. Really neat gadget. Started many conversations especially at night. With the 2-barrel on the engine, that light was on constantly.

For poops and grins, I used a fuel pacer switch in my baby blue 6-cylinder Hornet to illuminate a "Fuel Economy" lens in the gauge cluster.

Kinda hard to see here but it's the yellow lettering in the lower left quadrant of the warning lamps. I got the lens out of a Pacer cluster as some AMC Pacer's had a similar Fuel Pacer setup.

I have one NOS Fuel Pacer switch left. Don't know what I'm going to do with it yet. I had thought of using it to turn on some strip LED's in the cowl induction hood on my Javelin. That way, at night when you get on the go-pedal, the cowl induction will light up orange.

I think the idea was to keep the little light on as much as possible. Right?

No, to keep the light out.

Had one in a 75 Cornet back in 77. You actually had to be pretty tame on the pedal to keep it off. Anyone that new basic engine or motoring techniques would know without the light if they were driving " gas friendly " or not.