If that's how it works, that makes sense, but I read a different description.

"Offenhauser Dual Port intake manifolds feature completely separate runner systems for the primaries and secondaries. At low-load, the primaries feed the fuel-air charge through the smaller bottom passages at near sonic speed, improving power and efficiency. When the secondaries open, their charge goes through the bigger, cooler upper passages. Then, in turn, it is rammed into the cylinders when it encounters the high-velocity mix from the primaries. The result is better fuel economy and a 15-30 percent power increase across the whole rpm range."

To me, that sounds like it splits it evenly to all 4 cylinders, and the different runner sections deal with the primaries and secondaries, not different sets of cylinders?