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Engine – Cylinder Head ID

1975 1980 20R Cylinder Head:

Round Intake Port / Round Exhaust Port
80 / 81cc Chamber
In. Valve Dia. 43mm / Ex. Valve Dia. 35mm

1981 / 84 22R / RE Cylinder Head:

Square Intake Port / Round Exhaust Port
82 /83 cc Chamber
In. Valve Dia. 44.5mm / Ex. Valve Dia. 36.5mm

1985 / 95 22R / RE Cylinder Head:

Square Intake Port / Pear Shaped Exhaust Port
58 cc Chamber or 22RET (Turbo)
In. Valve Dia. 44.5mm / Ex Valve Dia. 36.5mm

Cylinder Head Intake Air Flow (Aprox):

Stock: 130 CFM
Stage 2: 160 CFM
Stage 3: 200 CFM
Stage 5: 250 CFM