Ram Horn Exhaust Manifolds
If one exists, it would probably be available through one of the Corvette clubs. Most of these manifolds were used on Corvette's. I have a set on my 62 Canadian Convertible with the 350 V-8, 76 truck motor.
I checked on some several years ago and remember finding them used all the way into the 70's on Corvette's.
Most of my research was done by looking at the ones for sale on eBay and asking the seller what vehicle they came off of. Or looking at pictures of cars for sale on eBay to find them.
There may very well have been another application but that's the one I'm aware of.