I just picked up some Autolite 25's for my stang, has cast iron Windsor Jr. heads on it, the one I just took out of the box is at .043 gap using my feeler gauges, what should i change it too, I know stock is .054, I also have an MSD box, should I go up at all?, Ive been searching alot on here and read alot of people actually going lower to like .040-.045 gap for better performance, or at least better start-ups, idling n such (low-rpm driving). I wont be beating on it, just cruising, would a lower gap be more efficient or a bigger gap?....Im changing the plugs for a 14 hour drive ill be doing soon just for extra insurance so what gap would all of you recommend? Thanks