B10 is the hex head and B11 is the round head. They were used in all GM cars from 1935-1966.


"It's just a phase. He'll grow out of it." Mama, 1964

1956 Chevy 1/2-ton 3100
1953 Chevy 6100 "The Yard dog"
1954 GMC Suburban Now with a new proud owner.