Btw,the air/fuel mixture is a ratio.If your moving more air you are naturally moving extra fuel to go along with it.At the same ratio that you were before you recent modsIf your plugs are tan than it's probably not quite lean enough to stumble,especially at one constant speed.Just because you are making more power doesn't mean the your motor is less effeicient and needs a richer A/F mixture to cope.Look at the Vettes making 500+ hp and getting 20-25 mpg+.More power doesn't always mean more jet.Pop the front bowl off and stab in a PV just for the heck of it.Jist my .02c