Tac wiring with y1 tic-toc-tach wiring harness

[Spartan]

I just bought an aftermarket harness from Y1.  My car did not come with a tach and I just had an original rebuilt.  Of course the wires did not come in the colors on the diagram they sent me but it should be easy enough to figure out.  The thing I am trying to figure out (and please let me know if I am wrong here) is where the wires connect on the back of the tach.  This is what I am guessing,  the original clock wire plugs into the tab in the center of the tach (looks similar to style and location of the clock I took out).  The square plug on the new harness goes into the pigtail coming out the right side (right if you are looking at the gauges from the front) and the round plug goes on the threaded bolt sticking out the top center of the tach.  I have never seen a round plug going on the threaded post before and there are 3 smaller nuts on the back I was worried a wire went on to but I can only guess I push it over the threads.

I have to get a good manual with all the info I need on it. My 1984 Chiltons seems to be missing allot of info

[71_deputy]

going from memory here

there is two terminals- both have a threaded nuts- one has a spade terminal- to the coil. usually a Grey wire-goes thur the firewall via a rubber grommet.

other is the 12 volt ower feed wire- dark blue- usually had a 90" bend in it to fit over the thread bolt.

Ground is via the case itself to the dash.

john Mac

[Just 6T9 CHGR]

This is a pic of mine before I got a repro harness from Bill Evans, so the correct colors are not represented.

The blue is the 12v+ switched from the radio fuse.

The green goes to the (-) side of the coil.
The grey single terminal plug (not shown) goes to the clock plug

[Spartan]

AH, so the tab in the center is for the coil wire to plug in to (green wire). The 90 deg (thats what I have) will slide over the post you have with the blue wire (yours looks like its attached with an eyelet instead of the push on connector).  That means the pigtail that comes off the right side is for the clock and not the tach correct?

Thanks guys, this has helped quite a bit.

[71_deputy]

10-4

[Spartan]

Very cool.  This may sound stupid but where does the hole for the wiring go?  I am not sure if there is already a plugged hole there or I have to drill one.

Thanks.

[Just 6T9 CHGR]

If the car wasnt originally equipped with one there is no hole in the fire wall

There is however a dimple in the firewall where the hole should be in between the bulkhead connector & master cylinder plate.

See circled area in pic

[8WHEELER]

Like Chris said, there is a dimple just below where the headlight vacuum hoses come out
through the firewall as seen is our pictures. That is where your big hole for the tach wire
harness goes.

Dan

[Spartan]

Really cool.   Thanks for the pics guys.   All of you have been a big help!   ANd dang, your engine bays are clean.  My engine looks premo but my bay needs a little TLC

[troy.70R/T]

I have a 70 charger R/T but there is no place where I can see that the tach wire comes through the fire wall. I have the dimple that you mentioned but I do not have vacuum lines for my headlights.  Would it go through the bulk head connector? any Ideas or pics?