jeebus @ mmw
+1y
There actually is no part number on them, besides 9, haha. Your not going to be able to find them at a local parts store, the only reason i can get them is because the manufacturer is just down the road from me, and i used to work there as a design tech guy, years ago, so I get to pull them off the line as blanks before they hit the threader.
They are not from an S-10, they are origionally intended for the mid 80s vettes, but are now popular for some circle track cars. They let me buy them with a blank thread on them, so i can put them in my lathe and machine them to what I need, then thread them myself to fit the S-10, other wise they would be useless as well.