5.000 BORE SPACING "NEXT GENERATION" HEMISPHERICAL CYLINDER HEADS, COMPLETE WITH COMPONENTS, ASSEMBLED, RACE READY

FOR GM APPLICATIONS FOR PRO MODIFIED, TOP SPORTSMAN, TRUCK PULLING, AND MARINE ENGINES. The Next Generation head was designed to be more efficient than the existing wedge configuration. The intake runner is located 180 degrees from the exhaust runner which provides a better path for incoming and exiting air. The combustion chamber is designed to unshroud both intake and exhaust valves while locating the spark plug in a more ideal position to enhance flame propagation. Rocker arms are positioned to give excellent valve train geometry. The exhaust rocker is over 75% longer than a wedge chambered head enhancing better spring life and smoother acceleration for modern high lift cams. Most hemispherical cylinder heads have ten 1/2 or 9/16 stud fasteners. Sonny's has incorporated twenty-two 1/2" studs necked down to 7/16. This allows better load distribution and more stud stretch for better clamping force. Supercharged applications can use straight half an inch studs. We used four extra studs in the bottom row to eliminate the stud from intersecting exhaust ports. Combustion chambers can have a range from 65 cc's to 95 cc without welding. Intake and exhaust runners are cast ported and have guide spacing to accommodate a range of 2.450 to 2.700 intake valves and 1.900 to 2.040 exhaust valves. With the chambers ported correctly, the intake will flow 615 cfm @ 1.100 lift with a 2.680 valve and exhaust will flow 425 cfm @ 1.100 lift with a 2.040 valve. We have found that this type head will make more horsepower, on a 800 cu. in. Pro Stock engine. This is because of better quality air on the intake side and a more efficient chamber. Sonny's also will offer rocker arms, valve covers, valve cover gaskets, aluminum blocks, crankshaft, 60 MM or 65 MM camshafts and sheetmetal manifold. This head is available to the general public in raw form or machined in different stages.