1957 235 w/Rochester - completely stock except for Pertronix ignition. (I thought the Pertronix might cure it but made no difference)

Hesitated bad and flooded a lot so I rebuilt the carb. This helped quite a bit but it still hesitates just off of idle. Once engine revs a little it has very snappy response.

The carb has a fresh rebuild kit in it as of this afternoon along with a new set of plugs. I made sure the link between the butterfly shaft and the accelerator pump is bent so that the pump is actuated just off of idle. One thing I noticed is that the pump once depressed doesn't spring back firmly (almost like the spring is weak) but since it is directly tied to the carb linkage, it seems to go along for the ride just fine.

I have tried timing a few degrees advanced relative to the ball / pointer - seems to help a little but still not great. Distributor / vacuum advance seems to work fine (it dumps the vacuum and sets the distributor against the mechanical stop in the furthest retarded position when I first stomp on it).

Any ideas? Seems like after all this attention the motor shouldn't be such a slouch off of idle.