Sounds like the Offenhauser dual port intake manifold gimmick. It also was a product of the fuel embargo era.
I bought one off a guy in my Engine Support Systems Class in college. Gave him 30 bucks for it, his asking price, I didn't haggle.
Put it on the 400 in the C body of the day, with a 750 Competition series AFB from a swap meet LOL.
It was, different. it actually did move the car easier, at tiny throttle openings.
At WOT, "meh" at best. A stock 4V intake would have been better at WOT.
It was a 2bbl motor, Beggars can't be choosers, and 4 barrels is (almost) always better than 2.
It was worth every penny of 30 bucks, though.
I later pulled it, cleaned it up and sold it for 50 bucks.
