Dual Carb Problem need help Options

[Cazz]

Any carb specialists out there? I need help with a carb problem.
-1974 2.0 with dual weber carbs
-The car is spitting and popping out the carb on cylinders 1&2and also backfiring alittle. I've rebuilt the carbs and pulled this carb off again completely taking it apart and checking with no obvious issues found
-With the car idling when I put my hand over each barrel on this carb there is no suction at all on my hand. The idle doesn't drop at all. Doesn't respond to any adjustments on the fuel/air mixture screws.
-The carb is injecting fuel streams when I open the linkage by hand
-On the carb on the opposite side when I put my hand over each velocity stack it really pulls air really hard on my hand and the car will bog down and shut off as it should.
-I have new intake gaskets an new carb base gaskets installed. I sprayed carb cleaner around the base of the carb and also at the head with no change in idle. Any ideas? Is this car basically running on 2 cylinders?
-On the opposite carb on cylinders

[98101]

Sorry for a newbie question... this is how I learn.

Cazz mentioned lack of suction from one carb, and people are talking about ignition timing. I'm not seeing how that follows. I thought the suction at the carb intake would be a result of each cylinder's intake stroke, piston movement and valve action combined with throttle butterfly position. Since the crankshaft ties piston movement together, I'm not seeing how ignition timing would cause a discrepancy in vacuum from one carb to the other. The way I understand it, suction from a cylinder on the intake stroke would be the same whether or not there was a successful spark during that cylinder's previous combustion stroke. I should be able to pull a spark plug wire and still see the same amount of intake air flow from that carb throat, right?

Or maybe I have it all wrong. Feel free to enlighten me.