Mystery Tachometer

Hi everyone, after a ridiculous amount of online research and coming up with absolutely nothing I decided to join a forum and hope that someone else has seen this gauge before. So I'm in the process of "restoring" my 1986 Chevy K10 Scottsdale, after 8 long years I've finally found the time to install the engine I rebuilt 5 years ago and the transmission I rebuilt 2 years ago. The truck now runs and drives and to my surprise all of the factory gauges actually work, they just needed to be hooked up to sending units. I've got the voltmeter, temp, oil pressure, clock, and fuel gauge working and I have my eye on the factory tach now.

This tachometer has the fuel gauge built into it, I can't find anything about this gauge anywhere, it's like it doesn't exist. Every gauge cluster I've ever seen either has the large fuel gauge next to the speedometer or they have a single tachometer and a small fuel gauge where the clock is. I haven't actually pulled the cluster yet to see how the tach is wired, for now I'm just super curious as to where this gauge came from.

Also, this truck has the body of a 1986 C10 and the frame/drivetrain of a 1975 K10 but these gauges look like the 1980s style to me.

(sorry for the crappy pictures, it's a pretty sunny day)

It's from a medium duty truck. A nice upgrade if it still works, imho.

Ha. That’s cool! How all squarebodys shoulda come from the factory.

bucket said:

It's from a medium duty truck. A nice upgrade if it still works, imho.

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Well dang, I never even thought to look at the bigger trucks but a quick Google search confirms it. The fuel gauge works and is pretty accurate so hopefully the tach works too. I'll have to pull the cluster and see if I can get it wired up. It would be really cool to get the whole factory cluster working again, minus the speedometer.

ma3600vz said:

73-80 Square Body Tach Dash Cluster Truck Tachometer Air Gauge Instrument Panel | eBay

Very rare square body tach cluster with air option and good mounting points. Very nice find. Per eBay policy this item has not been tested so it is listed as parts not only working. See pictures for condition and wear as we rely heavily on photos. Applications are based upon various sources...

www.ebay.com

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They can be had MUCH cheaper in farm country. You just have to find a yard that has old grain trucks.

I remember from years ago there was an outfit that was reproducing these in small quantities, but they wanted way too much for them. Something crazy like $300, and not sure if it had the gas gauge built into it like this.

ma3600vz said:

Chevy Truck Impala Oldsmobile Nova Tachometer Repair Restoration

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I thought I read that Tachman died. I wonder if someone else took over the business?

You got a clock so thats where the fuel gauge would go. When you get that option you get a tack with the fuel gauge. I have seen them before.

@

Ken Boellner said:

You got a clock so thats where the fuel gauge would go. When you get that option you get a tack with the fuel gauge. I have seen them before.

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You should read more of this thread.

bucket said:

It's from a medium duty truck. A nice upgrade if it still works, imho.

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^^^

Ken Boellner said:

You got a clock so thats where the fuel gauge would go. When you get that option you get a tack with the fuel gauge. I have seen them before.

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On the medium duty truck, the last gauge hole would have an air gauge for the brakes, or a vacuum gauge for the booster on juice brakes.

I got mine from LMC with a new pod and printed circuit. All works great. I had to cut a bit of the speedo hole with a unibit.

Do you kind know what year it came from i have a complete wiring diagram for 89 to 91 chevy trucks

Jimmyperf400 said:

Do you kind know what year it came from i have a complete wiring diagram for 89 to 91 chevy trucks

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Jimmy
That was installed on medium duty trucks, C50/C60.