I have been working on my brother's '66 Coupe with a 200 six. I talked him into doing a Duraspark II conversion on the car. I still think this was a good move as I believe the old "Load-O-Matic" dizzy was junk. So far, he has kept the Autolite 1100 carb but, I have read that once you swap the dizzy you need to swap the carb. The car will idle fine and accelerate fine but will not run smoothly at speed ... like cruising at 40mph. At a steady speed, the rpms go up and down every few seconds. If a carb swap is in order, what would be a good choice to go with the Duraspark II set-up?