Factory Tech Install?

[SourTooth307]

I was flipping through my newest LMC truck catalog in the interior section and noticed you can order directly from them the large tachometer and small gas gauge for my truck to get the gauge cluster setup I want. Since I'm sure this isn't plug-n-play, what would I need to do to get these to work with my 84's existing cluster? I have the large gas gauge next to the speedo and the blank spot in the lower left of my oil/volt/temp gauges.

After thought: My K10 has the dual gas tanks, would that be an issue if I wanted to use the small gas gauge that would go in the lower left?

[parrisc19844x4_468]

Originally Posted by SourTooth307

I was flipping through my newest LMC truck catalog in the interior section and noticed you can order directly from them the large tachometer and small gas gauge for my truck to get the gauge cluster setup I want. Since I'm sure this isn't plug-n-play, what would I need to do to get these to work with my 84's existing cluster? I have the large gas gauge next to the speedo and the blank spot in the lower left of my oil/volt/temp gauges.

After thought: My K10 has the dual gas tanks, would that be an issue if I wanted to use the small gas gauge that would go in the lower left?

Dual tanks aren't a conseration, most of our squares have them.
I am sure some of the exports will chain in. I dont think your casing will have the right plug in for the tach. Look at some of them for sale on ebay you will see what i am talking about. The tach has its own wiring harness. The gas guage may work, trace the circuit from where the small gas guage will do to where it goes in the pigtail. It should be two pink wires, if not you can just change the wiring on the pigtail. but I think you will need the correct cluster casing. Good luck.

[gmachinz]

You need to source a 1978-up tach cluster housing to keep it plug and play.

[ray_mcavoy]

^ Yes, to do a factory type plug & play install you'd need a 78-up tach cluster housing & printed circuit.

But here is a post showing how the regular non-tach gauge cluster can be modified to accept the reproduction tachometer & small fuel gauge --> http://67-72chevytrucks.com/vboard/s...8&postcount=20

[motornut]

Originally Posted by SourTooth307

I was flipping through my newest LMC truck catalog in the interior section and noticed you can order directly from them the large tachometer and small gas gauge for my truck to get the gauge cluster setup I want. Since I'm sure this isn't plug-n-play, what would I need to do to get these to work with my 84's existing cluster? I have the large gas gauge next to the speedo and the blank spot in the lower left of my oil/volt/temp gauges.

After thought: My K10 has the dual gas tanks, would that be an issue if I wanted to use the small gas gauge that would go in the lower left?

you could get the Tach/gas gauge and another small gas for the left...
Member Rich weyand did a write up on it.
http://67-72chevytrucks.com/vboard/s...d.php?t=629131

[SourTooth307]

Originally Posted by ray_mcavoy

^ Yes, to do a factory type plug & play install you'd need a 78-up tach cluster housing & printed circuit.

But here is a post showing how the regular non-tach gauge cluster can be modified to accept the reproduction tachometer & small fuel gauge --> http://67-72chevytrucks.com/vboard/s...8&postcount=20

So something like this would be a plug-n-play install?

[ray_mcavoy]

Originally Posted by SourTooth307

So something like this would be a plug-n-play install?

Yes, the factory tach cluster you have pictured there appears to be from the late 79 to 82 year range. The 1978 to 1987 gauge clusters are all pin-out compatible (with or without tach). So that will be a direct plug-in swap into your 84 since it is already wired for the non-tach gauge cluster.

The factory gauge wiring automatically takes care of the re-located fuel gauge because it routes the sending unit wire to two different pins on the cluster plug (the connection used for the large fuel gauge is simply left unused when you plug in the cluster with the small fuel gauge, and vice versa). And the tach is connected with it's own separate 3-wire harness.

About the only thing you might need to be concerned with is a vehicle speed sensor (VSS) if your 84 has factory cruise control and you want to keep it. I don't think the speedometer in that cluster you have pictured will accept the 83+ style VSS.

[SourTooth307]

Originally Posted by ray_mcavoy

Yes, the factory tach cluster you have pictured there appears to be from the late 79 to 82 year range. The 1978 to 1987 gauge clusters are all pin-out compatible (with or without tach). So that will be a direct plug-in swap into your 84 since it is already wired for the non-tach gauge cluster.

The factory gauge wiring automatically takes care of the re-located fuel gauge because it routes the sending unit wire to two different pins on the cluster plug (the connection used for the large fuel gauge is simply left unused when you plug in the cluster with the small fuel gauge, and vice versa). And the tach is connected with it's own separate 3-wire harness.

About the only thing you might need to be concerned with is a vehicle speed sensor (VSS) if your 84 has factory cruise control and you want to keep it. I don't think the speedometer in that cluster you have pictured will accept the 83+ style VSS.

My truck has very little equipment so it doesn't have cruise, or much else under the hood for that matter aside from the alternator and PS pump. The previous owner even took out all the under-hood emissions stuff so no AIR pump either.

[ray_mcavoy]

Originally Posted by SourTooth307

My truck has very little equipment so it doesn't have cruise....

Okay, sounds like you'll be all set with plugging in a factory tach cluster like the one you pictured earlier.

The fact that your truck already has the gauge cluster with the volt/oil/temp gauges is a key part of what makes this a plug-n-play swap for you.

As I mentioned earlier, the factory wiring should be configured to work with either type of gauge cluster. But it wouldn't hurt to double check your truck's cluster plug just to make sure it has the pink wire for the fuel sending unit going to both pins #7 and #18. The small fuel gauge in the lower left corner uses pin #7 so if you had to, you could just take the terminal/wire out of #18 and move it over to #7.

I think the 3-wire tach harnesses are being reproduced if you don't get one with the cluster and don't want to make your own.

[SourTooth307]

Originally Posted by ray_mcavoy

Okay, sounds like you'll be all set with plugging in a factory tach cluster like the one you pictured earlier.

The fact that your truck already has the gauge cluster with the volt/oil/temp gauges is a key part of what makes this a plug-n-play swap for you.

As I mentioned earlier, the factory wiring should be configured to work with either type of gauge cluster. But it wouldn't hurt to double check your truck's cluster plug just to make sure it has the pink wire for the fuel sending unit going to both pins #7 and #18. The small fuel gauge in the lower left corner uses pin #7 so if you had to, you could just take the terminal/wire out of #18 and move it over to #7.

I think the 3-wire tach harnesses are being reproduced if you don't get one with the cluster and don't want to make your own.

Yeah, I'm looking to spend the least amount of money on this since I don't really NEED a tach, I just want one. Modifying mine with the LMC truck stuff seems to be the easiest way to get there with as little $$$ spent as possible. Is this modification very hard to do in my situation?

[gmachinz]

And you need to source a tach filter as well besides the tach harness.

[ray_mcavoy]

Originally Posted by SourTooth307

Yeah, I'm looking to spend the least amount of money on this since I don't really NEED a tach, I just want one. Modifying mine with the LMC truck stuff seems to be the easiest way to get there with as little $$$ spent as possible. Is this modification very hard to do in my situation?

I haven't personally tried modifying a non-tach gauge cluster to accept the reproduction LMC tach and small fuel gauge. But looking at that link I posted earlier (http://67-72chevytrucks.com/vboard/s...8&postcount=20) it doesn't look like it'd be all that difficult.

And this is a good option too:

Originally Posted by motornut

you could get the Tach/gas gauge and another small gas for the left...
Member Rich weyand did a write up on it.
http://67-72chevytrucks.com/vboard/s...d.php?t=629131

You wouldn't necessarily have to put in a dual fuel gauge setup like Rich did either. You could just install that tach/fuel gauge combo from gmsports.com (http://gmsports.com/content/new-tach...and-gmc-trucks), leave the lower/left opening blank, and let your factory dual tank switch take care of selecting the sending unit like it does now with your large gas gauge.

Originally Posted by gmachinz

And you need to source a tach filter as well besides the tach harness.

Yes, many Corvette restoration parts suppliers offer reproduction tach filters (it's the same part # as used on these trucks). Here's an example of a reproduction that looks like the original --> http://www.ebay.com/itm/75-thru-89-C...-/331353521382

Some places also offer a less expensive functional replacement if original appearance isn't important. And some of the GM wiring diagrams show the internal component values (just a couple of resistors & capacitors) if you want to construct your own.

[rich weyand]

Originally Posted by ray_mcavoy

... You wouldn't necessarily have to put in a dual fuel gauge setup like Rich did either. You could just install that tach/fuel gauge combo from gmsports.com (http://gmsports.com/content/new-tach...and-gmc-trucks), leave the lower/left opening blank, and let your factory dual tank switch take care of selecting the sending unit like it does now with your large gas gauge....

Yup, like he said. And the gmsports tach/fuel combo gauge has the tach filter built in and comes with the one extra wire you need to install, the tach wire from the HEI distributor. Very simple install.

[SourTooth307]

Originally Posted by ray_mcavoy

I haven't personally tried modifying a non-tach gauge cluster to accept the reproduction LMC tach and small fuel gauge. But looking at that link I posted earlier (http://67-72chevytrucks.com/vboard/s...8&postcount=20) it doesn't look like it'd be all that difficult.

And this is a good option too:


You wouldn't necessarily have to put in a dual fuel gauge setup like Rich did either. You could just install that tach/fuel gauge combo from gmsports.com (http://gmsports.com/content/new-tach...and-gmc-trucks), leave the lower/left opening blank, and let your factory dual tank switch take care of selecting the sending unit like it does now with your large gas gauge.



Yes, many Corvette restoration parts suppliers offer reproduction tach filters (it's the same part # as used on these trucks). Here's an example of a reproduction that looks like the original --> http://www.ebay.com/itm/75-thru-89-C...-/331353521382

Some places also offer a less expensive functional replacement if original appearance isn't important. And some of the GM wiring diagrams show the internal component values (just a couple of resistors & capacitors) if you want to construct your own.

That tach/fuel gauge is a neat looking piece, but it horribly disrupts my OCD for symmetry and even numbers. Haha. That blank spot in the lower left annoys me more than I'm sure you guys can understand. I also have an OEM quartz clock I can stick there too but I'd rather have a tach if I'm going to start chopping the cluster up.

I didn't see the link posted earlier but yeah it seems easy enough to modify.