Tachometer calibration source?

[Dave69x33]

Does anyone have a source(s) that calibrates Camaro 1st Gen (GM in general) tachometers? 

How happy where you with their service and what is the average costs? 

The tack in my ’69 is in good shape cosmetically but I need to verify its calibration.  An initial review thru a web search I found Auto Instruments located in Collinsville, VA, autoinstrunments.com, 276-647-550.

Thanks in advance for your recommendations and feedback!

[68camaroz28]

Have not used it yet Dave but here is where we had our tach & gauges gone over. Know he calibrates tachs....
Gauge Repair-Gary Herbert at H&H Industries  tachman@bellsouth.net  1-800-327-8716, M-F 9-6 E.S.T

[Dave69x33]

Thanks 68camaroz28,

I'll add them to the list to consult.

Dave