Offenhauser Dual port ??

Well, look at how much port volume remains after the dividing wall has been added.

U are correct sir, with the dividing wall going from the carb to the heads, and the extra turns that the flow needs to make, when the secondary of the carb kicks in it is restriction time. the dyno do tell the truth, research it, and back in the day we looked at the cars that went quick-ld340