Im having gauge issues

[ChevyGuy1022]

Here's the thing... I had my car in the shop a while agto hooked up to a snap-on scanner and was monitoring things while the guy tried to figure out what's wrong with it. The engine trouble isn't my inquiry. My question is about my tach.
At idle, the tach reads about 1100, the scanner reads 750-800. At about 2000, the scanner says 1400. When I had the pedal down, it read 5500, but the scanner only read 4400.
Now... Can this be recalibrated or is it a broken stock tach? If it IS broken, how hard is it to replace and with what should I replace it?

Thanks for any info/thoughts/comments in advance.

-Chris

[Turbo V6 Camaro]

just get a aftermarket one and dont worry about the gay stock tach, they all lag and are retarded...

[3.8 nate]

http://www.autoinstruments.com/


for the stock look ;)

[ChevyGuy1022]

I've never taken these things apart... Can just the tach be taken out and replaced with an aftermarket gauge of equal size or is there specialty gauges for the cluster I need to find (such as the ones 3.8 nate directed me to with that link)?