FWIW: They sure aren't for ANY car with turbos....I Federally lab certed("LA-55" FTP) 288s, owned a couple, serviced several, same with F40s: no way IMO... ,,,the twin exit pipe configuration suggests scavenging sought after at HIGH rpms. not a street car application in my experience, based also on the slip fit jopints with springs-strictly racing car/track stuff...
I'll pitch in here. Those were the official manifold for the Ferrari 430 GT2. They were never built or distributed to the general public.
Thank you to every one here who chipped in to help. I really appreciate it. I had almost given up after a couple years and just thought to pop in and see if there had been anymore replies. Glad to know what these are now. Very interesting
Out of curiosity, since the F430 GT2's weren't made for the public, why did your company manufacture these manifolds? Also, why would any individual have bought them? (I purchased these in a lot of car parts at an estate sale in 2019 in Arkansas)