If my memory serves me right some of the factory 3 x 2 setups used progressive linkage with the two outside carbs completely closed at idle position, no chokes and no idle adjusting screws ( the rochesters didn't even have idle circuits on outer carbs). This way the engine idled on center carb and responded to about 1/3 to 1/2 throttle without opening the outer carbs at all this gave good drivability, better fuel mileage, and yet when you stood on it you had three fully functional carbs making horsepower. One of the reasons tri-power was no longer offered was most people didn't understand how to properly adjust it to make it perform, so the factories built bigger and better four barrels.
