carb help!!!!

I got a 235 with a 216 offy 2x1 intake with 2 carter w-1's car runs a little rough but drives fine but when you hit the brakes to slow down the car sputters and dies???? and it only dies when I am coming to a stop.WTF???checked for vacuum leaks tried tuning the carbs. Is there any other adjustments on the carb or just the idle circuit? anY SUGGESTIONS?

 

Float level a bit to high? both carbs syncroed evenly? what idle speed?