First of all 7.27 ET at 184? were you pulling a trailer to get the MPH so low for that ET? I have to believe that your engine hates the new intake configuration and likely has a reversion wave or the carbs are not even close to having the correct fuel curve for your engine set up. Did it run great on the dyno? If you have not tuned these carbs and intake on the dyno, that would be my next stop to save your entry fees and wasted time at the track. That single carb set up is awful impressive in a DOOR CAR at 7.27ET.
Are there any electrical draws on the battery at the same time this problem occures? Sometimes the battery will dip in voltage and create a ign misfire condition during the run. Are the wedge shaped floats in the correct side of the carb? In East and West carb applications we use wedge shapped floats to prevent the bowl from running dry on acceleration.
Bruce