Locked out distributor...

These MSD Start and Step timing controls are designed to provide an adjustable start retard to help high-compression engines crank over easily. Plus, they use a single-stage retard. They simply connect between the distributor and the MSD ignition. The MSD Start and Step timing controls feature two separate rotary dials for quick, easy adjustments. They require the use of MSD's ignition control.

MSD Start and Step Timing Controls 8987

advance is controlled by required msd ignition control, if dizzy advancing and retarding mechanically and by msd, spect it run all sorts of funny!!