Found this topic on Ausrotary...its a good read.
http://ausrotary.com/viewtopic.php?f=16&t=47212

Talked to a couple of other people...some guys refer to this motor as a "outer bridge" I never heard of it. But as I suspected it is to combine the driving manners of a street port with the power of a bridgeport. Makes sense I guess.

 

The center housing intakes are fed (primarily; there is a crossover slot in the manifold) from the carb primaries; the end housings from the secondaries.

Kind of a poor-man's 6-port, sounds like. Clever, but who knows how effective?