How about new coils? Didn't read your entire build thread but did you keep the original coils or replace them with fresher ones? It's amazing what new coils will do for your ignition. Ever since I installed a pair of Dyna 3 ohms in my 350, the ignition has been amazing. NIce, powerful combustion and rock steady idling. I also used a hotter plug, B7ES and the electrodes are now a perfect tan colour.