Steve, There are TWO different types that different people call original.
First, there is the type that most vendors sell, which are the type that look like the end of a regular stud or bolt and has a dimple drilled or machined into the end. I bought several sets of this type from Jerry M. Corvette vendor's also have these.
Second, My intake and Gary's (69z28-RS) intake from his HO Z has the type with the undercut machined at the end of the threads. I have seen several other examples of survivor type cars, and they had this type also. Please check out the tread of Chick's friend's Hugger Orange survivor Z, this car has this type of carb. stud also. (Look for the engine photo's in Chick's thread.) I think this type stud is very hard to find, and are THE original carb stud, especially for a Z28.
Bryan