This funny looking circle clip is used also used in a few other locations on the Corvette, it is the Corvette Shifter Rods & Clutch Rod Lock Clip.
*Note: This Shifter & Clutch Rod Linkage Lock Clip fits 1963-1981 Clutch Linkage and 3 or 4 Speed Shift Linkage. This is the G-Wire Style Retaining Clip, Not the C-Style That Fits Into Rods With a Hole Drilled Through the Tip Instead of the Groove for the C-Style Clip
TIP: Lubricate LIGHTLY with chassis grease.