What's the regulator set at? That's big carb for the street! No choke and double pumper, what kind of cam are you running? When it starts acting up do you see air bubbles coming up threw the fuel filter? Also look at the injector nozzle(accelerator pump) when you give it throttle and see if you have a good stream of fuel(no air in it).

Check the float levels in the carb. I always keep mine just below the sight plugs when running. This gives the fuel a little extra room to expand when it's hot.and not boil over into the venturis. Also, look down into the carb when it is acting up to make sure there is no fuel dripping from the boosters while at idle. If here is, it is flooding from either too much fuel pressure or something in a needle and seat assembly(which I don't think is an issue or it would do it all of the time).