Put Ignition ignition questions in the electrical section please.
You will find lots of trouble shooting stuff for the ignition there too.
Is this a stock chrysler ignition?
How old are the distributor cap/rotor/plug leads?
My hunch is you have bad plug leads or a bad lead from the coil to the distributor. Or both. Make sure all the plug leads are in the right order, clean and dry, and are not running close alongside each other.
In the dizzy make sure the rotor and cap are in good condition and that the reluctor is clean and the gap set to 8thou. Make sure there are no iron filings stuck around the magnetic reluctor.
Also just check you have a good ground from the dizzy to the engine and to the chassis. Make sure the ignition module is grounded well. There is a piece on checking the grouind connections in the electrical section too.