Cylinder Head: Valve Spring Installed Height
Installed height of valve spring must not exceed specification. Measure height from surface of cylinder head pad to underside of spring retainer. See Fig 1 . If height is greater than specified, install .030" (.76 mm) shim spacer on head under spring to bring height within limits.
CAUTION:
Install shim spacers only if necessary. Do not use more than 2 spacers, as this will over-stress springs and overload camshaft lobes.