Just a heads-up to those of you who plan to swap to a one-wire HEI. If your vehicle was originally equipped with a points-type ignition system (generally before about 1973), you must run a fresh line to the + terminal on the distributor from the ignition switch. Cars equipped with points had a ballast resistor or resistor wire in series with the hot line to the coil to reduce voltage after a few minutes of run time. 12v was supplied on initial start-up, then was gradually reduced to 6v to prevent burning the points. So, if you use the same line that was used with points, you will experience poor results with the HEI.