I've heard it has a lot to do with CA and their truck emissions laws..... something like no trucks older than 2011, and mandating electrics after a certain date, and trucking companies aren't investing in new diesel trucks that won't be allowed to run long enough, or something like that.
I work with castings. First is quantity. The reason is how you will make the pattern. If you only need one or two then you could do lost foam casting. If you want to do more then you can think about making a pattern. Also if you make enough parts you can justify the cost of the pattern. (If you only need 2 parts making a $1300+ pattern doesn't always make sense.) This is not even including the machining of the carb base, and head mounting surface and possibly jigs for that. Would a fabricated manifold be any better? I know single plane would be easy but dual plane may take some thought.
If you are just carving the Styrofoam you don't get the consistency but since you are not building a mold it's cheaper. If you are making a mold for the foam mold then they can be consistent. But you have the money in the mold.
If doing a duplicating thing, how about something along the lines of duplicating a 383 performer RPM with adapter plates? Dear proform, if you're going to make a crappy copy, at least copy something fabricated to a unique configuration, that will be worth the trouble of fixing. It ain't just Buick, that is for sure.
Summit doesn't care which generic product they show do they?? Thats a BBC intake and almost $800 for the Buick one.
I would love to buy a new B4B or two for the current engines I am building but at over $600 CAD it is not a good bang for the buck performance wise so I am just going to stick with the cast intake. I would certainly consider a stock appearing aluminum intake for less than that if you ever get one made Jim. Like you say. it would be great to see someone design an RPM style dual plane. That is right in the range of engine I am building. The SP1 is my next choice but I would much prefer a RPM mid rise dual plane. Greg