These screws are used to adjust the butterfly position/opening at idle. TheKnob is serrated for positive grip. 10-24 thread for the screw and nut.
GM Master Cylinder Single Reservoir Thumb Screw Cap Lid 'Use Delco Brake Fluid'
Holley QFT AED CCS Dominator Large Head Stainless Thumb Idle Screw & Spring
Holley QFT AED CCS Large Head Stainless Thumb Idle Screw & Spring
Dayco 91010 Hose Clamp Ss W/Plated Screw, Dayco
Dayco 91056 Hose Clamp Ss W/Plated Screw, Dayco
Dayco 91096 Hose Clamp Ss W/Plated Screw, Dayco