What’s this?

[Mark Osterman]

This came in a box of NOS carburetor parts

[Scott_Conger]

One of the many "cyclone" gee-whiz mileage quadrupelers available "in the day"

[Mark Osterman]

Thanks ... I was thinking that but couldn’t remember what they are called to do a search.

[tmodeldriver]

J. C. Whitney sold one they called a mini-supercharger. Somebody used to say that if you installed all of J. C. Whitney's gas saving devices you could start out with an empty tank and when your tank got full you could siphon it out and sell it to your neighbors.

[RichardG]

Mark, boy that brings back memory's , years ago when the flat head ruled the road I had a friend GEORGE PARKER, he was my age when I was 18, im 81, he helped me build a twin carb manifold for my 59-ab -- we used two strongburg 97's, this is where it becomes interesting, with valve grinding paste we pollished the inside of the intake ports by hand, with a sponge and stick, took many hours,did the same with the block,on the manifold we cut the base from one and did the same with the one we used for my engine, now this was before you could buy this stuff ,built a platform for each carb to rest on, he melted sulpher to seal the cuts, we made up the linkage and had to off set the generater now the interesting part, he took some 00 brass screen and a hard rubber ball the size of the ports on the manifold he pushed the ball into each port with the screen over the opening to make room for the butter fly to turn with out hitting the screen, used two gaskets one bottom and one on top of this screen. we did a bunch of other things to this engine too ,all this was in a 40 FORD club convertable, now this little beast was a hand full when you got after it, we endid uo poreing 3 or4 inch cement in the trunk with some added spring to boot, GEORGE told me that screen when the engine was wharmed up would fog the gas ,and with the two carbs pushing that mixture in the chambers boosted the power, by a lot, the first car to beat that old ford was a 56 chrysler 300-d .I had him for the first 100 yards, then that massive tank got its footing and gave me a cold when he went by, later i had a ride in that thing [he driving] 140 mph no sweat-- my engine is long gone but the ford belongs to a buddy, it now has a caddy engine. those were the days my friend--yup they were.

[John Codman]

I agree that the photo in the OP is a gas-mileage gimmick, but my Piper Comanche had a (very) soft Aluminum flow-director bolted under the carburetor. This was OE Lycoming. It was made of very soft Aluminum because it was not easily inspectable, and it was designed so that if a piece broke off, it would go through the engine without causing damage. One did, and it did.