Dual quads versus big hammer!!!...

they work like a vacuum secondary . If the secondary air valve opens to quick it bogs if to slow its lazy. the nice thing about the primary rods is you can change the jet size without changing the actual jets just by metering rod size.
if the secondary air flap opens too quick it bogs because there isnt enough fuel to cover up the hole created by the throttle plate opening because it doesnt have a secondary acc pump.How many holleys or avs or afb have you had to change a large amount of jet if there wasnt something wrong with the motor?Point is the calibration is always somewhat close.Just because vacuum is same doesnt mean the carbs are synced usually have to sync them somehow. also sometimes have to lessen jet size if plugs are too cold .