1987 318 Tuning with Summit Carb

They sure look like fuel restrictors. Have you tried calling Summit and asking who makes them? I think it might be Holley, but I really don't know. If you can get someone at Summit that will actually tell you, you could call them and maybe get more information.
Might need to do that. I'm having trouble finding info on this carb. The parts diagram didn't show them.