71. The manufacturer prohibits regrinding of the cylinder head, so a head with a deformed surface must be replaced.
72. Heads supplied for exchange may have a contact surface ground to 0.2 mm. Such heads are marked with the letter "R" knocked out on the tide of the head from the side of the distributor. They require a gasket 0.2 mm thicker than normal (a thicker gasket is marked with a notch on the protrusion of the gasket on the clutch side).