Engine masters did show about a few ignition boxes, I believe it was a vintage orange, Chrome and a new one that bough at the local parts store. One was bad the other was good up to about 5 1/2 grand then it failed and the new one worked the best. After that they ran the MSD6a with the best results. I would agree that the 6A is the best option if you are looking for performance. I did this conversion and love it. I would get a new unit because the older ones had components in them that heated up and failed.