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.

I know by the time I came of driving age in 1985 Offfenhauser was considered an obscurity taking a last place to Edelbrock Weiand and Holley. Offenhauser enjoys popularity to this day for making 4bbl intakes for inline 6 cyl engines. Back in the day companies converted Offy dual quad low profile intakes into blower manifolds.

Boom!!!! There it is.
Truer words have never been said.

I’d run a stock 2bbl intake and carb before I put on one of those.

And their “greatness” isn’t limited to SB mopars either.
They suck on everything.

Friend of mine has a 68 Camaro ss 396.
One of the local 396 gurus gave him a recipe for a 400hp hot street build.

9.5cr, comp 280h magnum cam, Ede 750 carb..... sp2p...... no headers.

He wasn’t to impressed with it, and after taking it for a test ride I could see why.
It was absolutely “done”(and wheezing) at 4500.
It really didn’t do anything particularly well. No great throttle response....... it was just a straight up dud.
I tried a Holley on it, which ran better, but didn’t feel like it made any more power.
It did make the motor behave in a way I’ve never experienced before or since.
After about 3500rpm or so, when you rolled the throttle open, you could feel it lose power....... instantly.
Like more throttle opening was messing with what was going on under the carb.

Once he commited to making some changes, he pulled it out and I dynoed it, just as it was in the car, ex manifolds and all.
It made an earth shattering 283hp. Yeh....... that’s pretty close to 400, right?

Headers picked it up about 30hp,

Changed to a small solid cam, rpm a/g, Demon 650dp........ made another 100hp and pulled strong to 6500.

For a mild street sb Mopar, I like the std performer......on 273’s thru 360’s.

Sounds like the Offenhauser dual port intake manifold gimmick. It also was a product of the fuel embargo era.