No, it is not the limiter. As
discussed previously in this thread, that has been checked. The Mallory box was even changed to a MSD digital 6AL2 without any change in the misfire. No news because the car is now in the shop. They have had it a week but I don't think they've gotten to it yet.
I will come back and report here when I get any more information. Just discussing it with them when I dropped it off, they think it is valve float. This is because I've replaced everything on the ignition. We will see.