Hi,
You have 236* of duration so you will not have a strong vacuum signal for the carbs to work properly. I would turn the idle up to 1,000 rpm [hot] and adjust the timing for 14* initial[disconnect vacuum advance] Late timing will not be good for air velocity. . Try and set both air screws for 1 1/2 turns out from all the way in. Check for any other vacuum leaks,etc. If your intake is a dual plane manifold your carbs should work fine.If it's an open plane manifold then you should go to vacuum secondary carbs. does your distributor have a vacuum advance? If not then a change to one with it set for 10* of vacuum advance would help alot.
Perry.
