Cylinder Head Specifications: Combustion chamber volume: 75cc / 84cc; Intake runner volume: 210cc; Exhaust runner volume: 70cc; Intake valve diameter: 2. 140"; Exhaust valve diameter: 1. 81"; Valve stem diameter: 11/32"; Valve guides: Manganese bronze; Deck thickness: 5/8"; Valve spring diameter: 1. 55"; Valve spring maximum lift: . 600"; Rocker stud: N/A; Guide plate: N/A; Pushrod diameter: 3/8"; Valve angle: 15°; Exhaust port location: Stock; Spark plug fitment: 14mm x 3/4 reach, gasket seat * Deck thickness: 5/8", pushrod diameter: 3/8". Vacuum advance distributor may not clear cylinder head.