3x2's are nothing but 1 2 barrel. Carburetors 1 and 3 do not have power values, power pistons or idle adjustments. The butterflies are thinker and fitted to be 100% closed. Them operate on progressive linkage. 4x2's are 100% 2 barrels and not progressive.
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There's some accurate and some very ignorant information ^^^^ here ^^^^....
On a Tri power set up "3 2s"....
Even though they have thicker throttle plates that stay "sealed" at cruise, they are still otherwise normal carbs with jets, float bowls,
accelerator pumps, with 2 venturies, and yes they absolutely do need to be synced to open at exactly the same time and to work in progressive harmony with the center 2 barrel carb... If the linkage is uneven, one outboard carb will crack open before the other, causing a massive stumble, localized lean conditions in specific cylinders, and terrible throttle response. You are syncing the linkage mechanical timing, not the idle screws.
As for your "4 2s"
They can be run on solid linkage (all four opening at the exact same time) or they can absolutely be run on a progressive linkage (just like the "3 2s") where you cruise on two and drop into all four. In fact, running 4x2s without a progressive linkage on a street car usually makes it nearly undriveable because it bogs the engine down with too much air too fast.