I know this schematic looks sort of chaotic; but this is the belly shield that keeps air flowing under the car without creating lift.
GM part #'s
#22765382 under pan
Not sure exactly how many nuts and bolts
At 200 mph + this might help!
Pedders Pace Car Package, Injen CAI, Flowmaster AT, AAC Lighting, ZL1 fascia/skirts, RKSport Ram Air hood, vented fenders, painted stripes (Gary's Customz), Honor and Valor badged (Thank you, John)