This is an original pair of GM high performance cylinder heads for Small Block Chevy engines. The casting number on each head is 3927186. This casting is known as a "camel hump" or "camel back" head due to the double humps cast into the ends of the head. The camel hump heads were reserved for the higher performance Small Block Chevy engines. These particular heads have the 1.94 inch intake and 1.50 inch exhaust valves which were used on 350/300HP engines. Chevy also used these heads with the larger 2.02 inch intake and 1.60 inch exhaust valves which were used on the Z/28 302 engines, LT-1 350 engines, and other…