I think you're referring to the "clamps", that together bolt the intake and exhaust to the head. Those are just referred to as "intake\exhaust mounting clamps" I think. If not, then you can pass that description along to any GM parts counter person (along with a your engine casting number) and they should be able to get what you need.
If this part is no longer available then call around different salvage yard. Most will let them go for 5-10 bucks at most. Get as many as you can possibly, while you're there. It's not like they'll be back in production.
Also, the 216-235-261 series clamps will work on the later 194-292 sixes. Might have to do some minor work at the grinding wheel but they'll hold true.
I am very sorry if I confused anyone. I am used to the other boards I visit that have a much smaller crowd. I am in fact refering to a 292. Once again sorry for the confusion.