Get a Chrysler Electronic unit from Don from FBO.
His system will rev to 8000 rpm without a hickup.
Very inexpensive system. I just bought his coil,ecu,and ballast resistor for my /6 car. Then I bought a rebuilt distributor for a 73. Hooked it all up,and the ignition is solid. Car revs like a beast. Give him a call and chat with him.
He has thousands of satisfied customers. Once you talk with him, you will be sold.
www.4secondsflat.com