If you're not running a vacuum advance type distributor you will have a terrible time
with heating at cruise. When you start the combustion too late in the cycle the
exhaust valve will shut before all the heat is out of the engine. No amount of band-aid's
will fix this. You will also a gain in fuel mileage and response. It's just amazing what
those Ford engineers know. I learned the hard way,too. Hope this helps, Steve