Retrofitting Tach
 

Our wagon being an 80, has the single large clock on the far right of the cluster.

I was at the pick-n-pull and ran across some complete clusters for $14.00 complete (bought 2) and plan to retrofit the tach/clock gauge into it.

The pickup was attached to the engine at the time it was installed so I pulled the tach amp, tach amp bracket, wiring almost to the fuse block, and the fuse block.

Being my search didn't come up with a completed installation, I can only hope that the wiring schematics in the manual are correct.

i would guess it is a fairly srtaiht forward deal as long as you have all the components and it sounds like you do

sorry i am of no help besides that

The biggest thing is getting the wiring harness from the tach amp, to the cluster. You will also need the correct tach, said amp. IIUC, you have the gray wire sending unit, sensor, that goes from the crank to a bracket, I think you need that too, that plugs into the amp, goes to said harness, etc.
I have a pic that may help, too large to send here.

I have the pickup at the flywheel and the grey wire with the plastic end installed.

Yesterday I picked up the amp socket and amp along with as much wire as I could get. I originally wanted to get the wire including the ends as it attached to the fuse block, but gave up "feeling" that it was at the very least a 2 to 4 hour project by itself (to close to closing time).

With the wires going from the amp socket to both the fuse block and tach. I need to sort those out and if you pic can help that would be awesome and appreciated.

I did realize that I did not get the female plug for the gauge and will therefore have to make another trip to get one for a permanent install. I will use butt-end connectors to prove it out.

The cluster came from a 300D which had about 6" of the grey cable coming out of the socket (engine was pulled) and therefore assume it operates off the flywheel pickup as opposed to the trans and or EGR hookup types that I have read about.

Sounds like you've got the correct tach.
My camera is dead, (FWIW, stay away from Olympus) don't think pics would help anyway, as all the wires are bundled together.