As mentioned info battery 1st thing and Speedo cable. Remove front seat(way easier to lay on floor. Heat cables may need to be removed I think???Drop column.
I dread doing this but I gotta get the tach out and recalibrated.
Make a list before doing it and do it all at once to save the bs
I seem to recall Classic industries had tachometer with modern circuitry around $200. I debated installing one in mine though it wasn't on it originally