David what you are describing sounds to me like a ground issue. Have you run a separate temporary ground from the _ battery post to the engine? A points bracket screw being loose can cause problems. Some points come with and some without the bracket that they mount on. Did you change the condenser bracket as well as the condenser? The condenser ground will cause that type of problem. Also i had a wire broken within the insulation from coil to the points that took me 2 months to find. Also you could hook a analog volt meter to the - side of the coil and watch it while the tractor is trying to die and see if you are loosing fire.