Tachometer in clock location

[tucsonjwt]

I want to replace the clock in my 83 C20 with a small aftermarket tach. I have seen pictures of this but I don't know how the tach would mount to the cluster backing plate. The factory clock has two offset mounting tabs which mount to the cluster, but all of the aftermarket tachs I see mount to their own housings.
Has anyone done this. Thanks.

[Factory Guy]

You can do it. I bought a standard 8000rpm Bosch tach (not the one from the aftermarket) for my Square and mounted it in the Fuel gauge location (i know not what you want). I had no mounts for any of it I just did it. I am sure you could mount yours in the clock location, instead. The tach itself is not large. The biggest problem you will have is making the face for it.

To see my build on the tach, its in my link below, it starts mid way down the on that page.

https://67-72chevytrucks.com/vboard/...=791250&page=3

[chris989]

Originally Posted by tucsonjwt

I want to replace the clock in my 83 C20 with a small aftermarket tach. I have seen pictures of this but I don't know how the tach would mount to the cluster backing plate. The factory clock has two offset mounting tabs which mount to the cluster, but all of the aftermarket tachs I see mount to their own housings.
Has anyone done this. Thanks.

Not to change your plans but have you considered the LMC tach kit,, did mine and was very pleased.

Chris

[tucsonjwt]

Regarding the connection to the HEI distributor, I see two different styles of connector/pigtail for the distributor. One style is just one green wire (for the tach signal, I presume) and the other style is a combination connector with one red and one green wire. Which connector is appropriate for my 83? What is the red wire for? Does it supply ignition on switched power?

Thanks.

[ray_mcavoy]

Originally Posted by tucsonjwt

Regarding the connection to the HEI distributor, I see two different styles of connector/pigtail for the distributor. One style is just one green wire (for the tach signal, I presume) and the other style is a combination connector with one red and one green wire. Which connector is appropriate for my 83? What is the red wire for? Does it supply ignition on switched power?

Thanks.

Yes, the red wire on the combination connector is the switched power feed to the HEI. But you should already have that wire/connector as stock equipment on your 83. So all you really need is the separate single connector that plugs into the "TACH" terminal on the HEI.

[tucsonjwt]

Just to clarify, I was wondering if I inserted the two wire plug into the distributor cap, could I then run wire from the two red and green wires to supply switched power to the tach as well as signal feed from the distributor to the tach? In other words, could I avoid connecting to ignition on switched power from the fuse block? Thanks.

[ray_mcavoy]

Originally Posted by tucsonjwt

Just to clarify, I was wondering if I inserted the two wire plug into the distributor cap, could I then run wire from the two red and green wires to supply switched power to the tach as well as signal feed from the distributor to the tach? In other words, could I avoid connecting to ignition on switched power from the fuse block? Thanks.

No, unfortunately the combination plug wouldn't be a convenient way to supply ignition switched power to the tachometer.

That's because the combination plug takes the place of the existing power feed connector. In other words, you can't leave the factory power feed wire / plug connected to the HEI cap and fit the combination plug in along with it. And of course, that would leave you without any power going to your distributor unless you rigged up a way to connect both your factory power feed wire and tach power feed wire up to the red wire pigtail on the combination plug. That could be done with a splice (ugly and would involve cutting the factory feed wire) or some additional plugs & connectors. But tapping power for the tachometer from the fuse block would be an easier and cleaner looking solution.

[tucsonjwt]

Ok. I will just run the green wire to the tach port on the distributor cap and pick up switched power from the fuse box. Thanks.