AVS throttle screw retainer

two of the carbs are 4966S from 69-71 440s, and the other one is off a 383 N code, all have the same bushing. and it must be original, because of the tab on the bushing to stop it from turning when tightening the idle screw, and a machined slot in the casting to hold that tab in place. i just called a local carburetor rebuilder and he says that its an original part, and he gets people calling for this part every now and then, but he hasn't found a supplier, all he does is double nut the screw, when he needs one, but to me that seems like a pain, so i'll try the plastic wall anchors. also because of the size of the bore that this bushing goes in, threading it to accept another screw wouldn't work as it would be to weak.