I got a Mopar electronic ignition for my 1970 Challenger, but it came with no instructions for wiring it up.  I'm putting this car together from scratch, so I have nothing to go off of.  I am currently under the impression that the wires go as follows:

Black/white and Grey/black:  to distributor

Black/yellow:  - side of coil

Blue/yellow:  Feed side of ballast resistor

Green/red:  not used

Please help if you can.  Also, do I need to use a ballast resistor?  I thought they were mainly to avoid burning up your points. 

Thanks

yes you need the ballast resistor it breaks down the voltage so you do not burn up the coil the wiring is correct  

My Mopar.com has a great wiring diagram, you can look it up on the internet.  

look under electrical specs at my mopar.com