Where in Sweden are you?
You have Topplocksverkstan outside Lund, with the guru Erland Cox.
In Vadstena PMM.
Arvika Overboostracing.
That's 3 from the top of my head
//Hasse
That's the speedo not the tach .
Here are only wire for speedo.
And here is a plug where the tachwire should go, so it must be electric.
Let's see some schematics.