24502559

Chevy Small-Block V8 | Cylinder Heads | 24502559


24502559 - SB2 Aluminum Racing Head


These new SB2 (small block second generation) heads are designed for maximum effort competition, improved durability, simplified preparation procedures, and reduced overall cost of building and maintaining an S/B V8 racing engine. The intake valve ports are relocated to orient the intake runners toward the carburetor. The result is a distinctive "mirror port" arrangement that is a significant advance over conventional siamesed and symmetrical port designs. The exhaust ports remain in the traditional siamesed center port design with coolant passages between the ports that eliminate the need for additional machining and auxiliary water lines. SB2 heads provide "out of the box" airflow performance that is comparable with highly modified conventional castings. The revised valve layout improves valvetrain reliability by improving pushrod angularity and reducing or eliminating rocker arm offset. It also enhances piston durability by changing the depth and location of the valve pockets in the piston tops. The intake valve angles are 12º by 4º and the exhaust valve angles are 8º. The as-cast combustion chamber volume is 28cc; intake volume is 196cc. Recommended intake valves are 2.15" and exhaust valves 1.625" with valve length of 5.55" and valve seat intake 2.20" x .312" and exhaust 1.67" x .275".
Technical Notes: A Special block P/N 24502600 (with revised lifter spacing/angles) is required only when using a flat tappet camshaft. These heads also require the following special components: upper intake manifold P/N 24502588, lifter valley cover P/N 24502587, spring oiler kit P/N 24502597, head gasket P/N 10185054 and rocker cover (not available). The following aftermarket items are available: head bolt kit from ARP P/N 234-4722; camshaft from crane flat tappet with 106º lobe separation P/N PL950266 and 109º lobe separation P/N PL950276 and roller cams are also available; rocker arms from Jesel; pistons from JE; special gaskets are required from Fel-Pro; valley cover P/N 1242; rocker cover P/N 1655; intake manifold, .030" thick P/N 1237, .045" thick P/N 1237-2, .060" thick P/N 1237-3, .090" P/N 1237-4, .120" thick P/N 1237-5. Wrench clearance for the nut on the short outer studs is limited. A 7/16" 12 point box end torque adapter (Mac Tools P/N XB142 with 3/8 drive) is recommended.