Do you think 10.5 power seem like to much. The carbs both came with 10.5 power valves in them. Vac at idle cut in half is supposed to give you power valve size right. But what about if your running 2 carbs is that cut in half again? I just fouled my first set of plugs. Power valves don't come in till it's under load but but if there the wrong size could they dip into the idle circuit? 2# 750 dp holley vac ref power valves on a 6-71. It took awhile for it to foul out the plugs. I've been driving it around town without problems. When it did foul out it was on the way home from a car show in the rain. So I was driving slow and not really giving it to much pedel on wet roads. Anyway I was wondering if anyone has any thoughts on these power valves. Thanks.