Cylinder Head Specifications: Combustion chamber volume: 170cc; Intake runner volume: 245cc; Exhaust runner volume: 105cc; Intake valve diameter: 2. 32"; Exhaust valve diameter: 1. 94"; Valve stem diameter: 5/16"; Valve guides: Manganese Bronze; Deck thickness: 5/8"; Valve spring diameter: 1. 54"; Valve spring maximum lift: . 700"; Rocker stud: N/A; Guide plate: N/A; Pushrod diameter: 5/16" or 3/8"; Valve angle: Int. (stock) / Exh. Tipped 1. 5° - 21. 5°; Exhaust port location: Stock; Spark plug fitment: 14mm x 3/4 reach, gasket seat. * Our new Victor Jr. Cylinder Heads are designed for high output 650+ HP Chrysler 426-572 HEMI(R) engines. They feature fully CNC'd combustion chambers and CNC blended seats for optimal air flow performance. These cylinder heads also feature a revised exhaust valve angle to accommodate larger intake valves. They also feature brass tubes installed in exhaust pushrod holes to allow maximum clearance with minimal port intrusion.