Tach adjustment v6 to 4cyl

[Afromankam]

I have a 89 HB Pickup that I picked up a pathfinder cluster with factory tach for. Is there a way to adjust the tach so that it reads the 4 cyl engine properly?

Also, is there a proper way to re-set the speedo needle? Had to replace my broken one and speed is off buy a good bit.

Thanks in advance!