The cast iron Super Street heads have been designed for applications where extremely high torque is necessary at low rpms. SS heads work well for hot street engines, boats, tow trucks etc. where rpms under 5000 are the main concern with a relatively low lift cam. The Super Street heads replaces standard small port heads with new technology, enabling the small port size to create wicked torque. In fact, these heads prove to produce more HP and torque than any other production head below 4000rpm. The Super Street head maintains OE 429/460 stock factory valve angles & spacing. SS cylinder heads use any standard 429/460 wedge flat top piston and OE 429/460 guide plates and stud girdles fit perfectly. Comes standard with bolt down pedestals like D3VE type heads, but can be upgraded to screw in studs. Has 98cc combustion chambers typically designed for lower compression engines. Uses small 2.08” intake valves (with 240cc ports) and 1.65” exhaust valves (with 87cc ports), yields high port velocities for maximum torque. Super Stock heads use small standard size intake manifolds and exhaust. May be purchased Blank: no seats cut or guides sized.