Hello Ed,
In ref to the tach transmitter unit:
I’m not sure I have any value added feedback, but I thought I’d share a photo of the guts on my unit, in case there’s something you can compare.
Note: Because I was disappointed in how long the single battery configuration last on the tach, I soldered jumper wires over to the other side of the box, so I could install a second battery. I’m much happier with the life now.
In ref to my soldering job, I know, there are big blobs. But hey, I’m the kinda guy who uses a pound of nails for a pound of wood.
FYI, I believe I did a write up on my installation of the tach system years ago but I couldn’t find it. I’m not very good at searching through the archive threads. Anyway, I got lucky and found period correct components at a swap meet. However, maybe it’s the engineer in me, I like things symmetrical, so I mounted the tach transmitter unit on the driver side inner fender under the hood (opposite side to the battery regulator). Looks like it belongs there and well protected from road grime.
Best of luck!