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; Guideplate: 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.