I had a similar problem with my 6.3. It would start running on four cylinders and then it would shut off. This was one of the two sets of points that was badly insulated. The clip holding the black wire on the moving part of the points was not properly in place and was too close to the metal. While heating the metal would expand and enter into contact, shorting the citcuit. Have you tried the M-100 board? www.M-100.cc You have true experts of that model there who will help you out.