67 Specific Tach Install Questions

[A.Bursell]

Hello-

I have searched and searched and not been able to come up with answers to my questions. I have just finished installing a really nice factory 6-cylinder tach in my 67 C10 and now it's time for some wiring.

I am aware that in later years the brown wire passed through near the lower left corner of the fuse box, but I cannot find any info specific to 67. I recall in 67 the wiring may have passed through the firewall in a different location, but I cannot find any info on that. Can anyone help? I know I can make it work, but I want it to be correct.

I do have a factory wiring harness (or part of it that I am repairing), so it has a grommet on it already. Other than measuring it, does anyone know the correct hole size?

Also, where on the fuse box is the correct location for the tach to plug in. I know there are several options but I would like to use the correct feed.

Thanks!

Adam

['68OrangeSunshine]

Adam, you might get more expert advice on the Electrical Forum.
I gotta work tomorrow or I would look it up in the '67 Service Manual under the wiring diagrams, but My '67 K/10 Suburban didn't have a Tach. The Tach on the '68 C/10 Stepside is aftermarket, [Auto Gage], so I can't help about "Factory" type set ups.
But here's a bump.

[TBONE1964]

I will subscribe because I want to know the facts on this as well. I know the 68-72 grommet holes are 3/4 inch but do not know about 67 only.

The 67 only tach wiring harness that I looked at from Ecklers did not show it with a grommet (maybe a photo error).

I hope someone has some information they can share for your benefit as well as others.

Take care,
Tom

[FirstOwner69]

Here's a picture of the assembly manual page in what appears to be the 67 portion of the manual showing the wire running through the same grommet as the oil pressure line.

[A.Bursell]

This is great- actually answered all of my questions and tells me that I actually have a 68-72 wire harness. Would be great if someone actually had a pic so that I could see if it is a 2-hole grommet (similar to windshield washer) or if it just shares space with the metal hard line. Anyone?

Let me sum up answers for search purposes.

1) The 67 tach wire passes through the firewall at the same location as the oil pressure line.

2) There is no grommet on the wire harness and no additional hole. (The Ecklers catalog appears to be correct.)

3) The tach should plug into one of the locations marked Ignition Unfused.

Thanks for the help- and if anyone has a pic or additional info that would be great.

Adam

['68OrangeSunshine]

I wonder what color the factory wire [1] is? I'd like to replicate it on my next project. Thanks for pointing this out, I usually just use what ever colored wire I have the right length of, from a selection of repurposed electric lines.

[A.Bursell]

Originally Posted by '68OrangeSunshine

I wonder what color the factory wire [1] is? I'd like to replicate it on my next project. Thanks for pointing this out, I usually just use what ever colored wire I have the right length of, from a selection of repurposed electric lines.

That's actually a great question. I assumed it was brown like the later years but probably need to double-check as well.

Adam