As best as I can tell, according to my Haynes manual (for a 4AGE dashboard):
* Tacho - B (pin 4) on the 8-pin dashboard plug. Goes to the Igniter (

)
* Water Temp - BR (pin 11) and Y-G (pin 12) on the blue 12 pin dashboard plug. Pin 12 goes to the water temp sender.
* Oil Pressure - Y-B (pin 4) on the brown 10 pin dashboard plug. Goes to the oil pressure sender.
* Volt Meter - no specific wire that I can see - it appears to just connect directly to the ignition and an earth (both of which should already be in the dashboard loom).
From the diagram it appears that the wires stay the same colour all the way from the motor to the dashboard, so it should just be a matter of tracing the wires through from the dashboard plugs to the engine loom plug.
If you are still stuck and need it you are welcome to borrow my Haynes manual, I'll be racing in Massey on Sunday or you can pick it up from work (in Westgate) next week. PM me if you need it.