Stop in for a cup of coffee

Eddie bought a factory tach that mounts to the console and it reads off...

He was reading somewhere that there is a way to "recalibrate" it so it will read correctly...

Maybe we can get @Eddie348 in here to see if he can remember what it was or give us a link on how to get the tach to read correctly...
The kids gave me some gauges a few years ago for the pop so I have to kind of use them, I will get a pic hard to explain. POS stuff but look cool.