Tachometer Testing

[Gary AAR]

I am working on restoring the rallye guage cluster in my 1970 Cuda with 340 factory standard ignition.  Anybody have any restoration tips on the tachometer, or how to test the tachometer for proper operation?  The needle seems  to have a lot of drag when I try to rotate it by hand.  Maybe just needs a good cleaning and lube?  Just trying to avoid the cost of sending the tach off to "Auto Instruments", "Performance Car Graphics", or "Instrument Specialties".  If it comes down to sending it off, anybody have any experience with "Auto Instruments", "Performance Car Graphics", or "Instrument Specialties", or is there someone else I should consider?
Thanks for the help.

[Car-nutt]

I have used Auto Instruments, great guys to deal with excellent after sales service if you have any questions after the fact.

[BIGSHCLUNK]

We have a guy here in town who tested mine. Gave her a little shot of oil and I was good to go. Said I was dead nuts on. Also told me I had the "correct" tach . Seems many have been refaced to look correct but are not. BTW they are SW's 

[dodj]

Rebuilding the tach yourself is not difficult.

https://www.rt-eng.com/index.php/67-74_Tach_Board_with_Calibrator_Built_In.html

[Chryco Psycho]

 
I have done a number of tachs this way using the RTE kit but you need to buy the calibrator as well