1968 Dodge Charger wiring Question

[Hazzard Lugnut]

Could someone please tell me if and how I can use my factory gauges + a triple gauge set that mounts tounder the dash. And what the purple and black wire and the green wire goes to

 

[Shorthorse]

I believe those are the alternator wires. Sometimes you can tell by their position in the harness itself. If the harness is in place, what are they closest to? Here's something better that my guessing. See diagram "B". It's for the engine compartment wiring.
http://www.mymopar.com/downloads/1968/68ChargerA.JPG
http://www.mymopar.com/downloads/1968/68ChargerB.JPG

 

[Beekeeper]

To use the triple gauge set you can use a tee at the oil sending unit port for oil pressure and for the temp gauge it looks like you have an aftermarket intake do you have a extra coolant port not being used? Of course for your gauge lights you need 12 volts. the orange wires are the dash light circuits. Oh and your volt gauge needs to come off of a switched 12v source and other side of gauge to chassis ground.