<VV> Running Badly Again

[William Hershkowitz]

                                                                           B'H
Hi all...My 1966 Monza 4 door  with air conditioning and Powerglide was running fine except on a hot day with the A/C running, when after the engine warmed up, it would stall at every red light in slow city traffic.
Call me dumb, I asked ChatGPT what would cause that problem, and it said probably heat soak/vapor lock.  Of course I use an electric fuel pump mounted next to the gas tank, and when the A/C isn't on, the car runs fine.  Ir suggested using phenolic carb spacers sandwiched with  thick carb gaskets...
Well, the car doesn't run fine any more.  It ran so roughly that when the A/C compressor is engaged at idle in Drive, the fan belt flies off the pulleys!  This isn't a big deal to put back, since I have Ken Hand's spring-loaded tensioner.  
I checked the timing, at idle in Drive, vacuum advanced plugged, it was way over at around 32 degrees TDC.  I corrected this and got the idle running smoothly.  I adjusted the mixture and idle screws, as well as the idle solenoid, which got the idle running okay with the compressor engaged.
However, when driving now, there's a very noticeable miss of some sort.  She "bogs down" and misses when accelerating.
I checked all the vacuum connections and they look fine.  I didn't have a chance to check the carb holddown nuts, but the carbs are solidly bolted to the intake manifold.
I also noticed that the new carb base gaskets don't have those 2 notches.  Could that make a difference?  Perhaps I should put the old gaskets/spacers back?
Any advice would be appreciated, Thanks!  Bill Hershkowitz