Adding a tach question

[J Knight]

your picture = 1024 words.

It appears that the tach-able housing ALSO includes mount points for the lower left gauge (needed) and removes some weird circle.

the blue looks an inch or two wider in the pic - its just a perspective issue from the pic right?

I believe these clusters are from a 76-77 because of the hole for a mechanical oil pressure gage and the three prong volt gauge location. The lower left gauge position appears to be for a brake warning light. Your cluster may be different in that spot if equipped with a clock.