Originally Posted by 27TRoadsterguy
I am in the middle of installing 3 Weber 32/36 progressive 2 barrel carbs, each on its own tubular manifold, on my 6 cylinder 292 Chev engine. A friend of mine suggested connecting the three manifolds with "balance tubes" his logic was the engine will not be as finnicky to unbalanced carburetor fuel/air flow. Is this really necessary? I have seen this engine with three side draft carbs (DCOEs), and never any balance tubes. Balancing carb airflow is a matter of putting a vacuum gage on each carb, adjusting the carbs so the vacuum is balanced. My MG and my Healy and my motorcycles were all this way. Is there any need?
Your friend is onto one of the major reasons for balance tubes, the others being that any one cylinder can at least theoretically see the area of all the venturies, the third is a source of steady(er) vacuum for power brakes.
If those are not a concern and you don't mind balancing each carb like you do on your bike, no balance tube is fine.