What were looking at is the working side of an  early ’50′s Edelbrock Model R Racing Cylinder head. When new a pair of these desirable heads cost $74.50. According to their catalog they were cast out of the finest virgin aluminum, heat treated and aged for maximum strength an hardness. They had larger capacity water jackets and would bolt right up to a stock block if you changed out the lower cylinder head studs. Of importance in their design process was the extra wall thickness maintained over the combustion chamber areas and the extra supports inside the water jacket for added strength. They also used 14mm spark plugs. You had your choice of 8, 8.5, 9 and 9.5 compression ratios. Depending on your piston package a 9.5 head would actually give yo 11.4 to one. Vic and Company recommended relieving the top of the block 3/16″ for better flow characteristics. JMC_3631 (C) AHRF.