Corvette Camaro Chevelle Nova Impala GTO Firebird 442 Cutlass . Ac evaporator BOX 1/2 mounting bolts. These mount the two halves of the box together. C head marking, 3/8 hex head. Recessed flanged head. 1/4-14 thread w/self tapping notch cut into the end. They do not reproduce this style of bolt. 45 shipped to the lower 48.