[Rick Parker]

I had an experience a little over a year ago that opened my eyes.
I wanted the replace the distributor cap (black original MSD item) on my MSD (289) small diameter pro billet distributor with a new design (red) that MSD had just brought to the marketplace. I installed the cap put fresh Autolite race plugs (cut back gap) and the engine would not rev past about 4500 rpm. I changed wires to Holley 9MM resistance type with the same results. So I put the original wires back on (wasted $60). I then began to look at the dimensions internally between the two caps and there were some alarming concerns. The tip of the rotor was passing the cap contact about .160 below the end of the tower contact creating a huge air gap that I thought was part of the problem. I contacted MSD to point it out and the said in their testing it had not been a concern. I removed the cap anyway and put a replacement of the original black one on. I still had the same miss with the original wires and distributor. What solved the problem was the installation of a plug with a resistor in it. For some reason even the resistor type wires didn't have enough of a choke in them to allow it to function properly. After installation of the resistor plugs all was well. This still baffles me to this day, currently I run solid core wires with no problems.

Rick