The twenty-seven Gb500 Touristtrophy 1989 (k) Usa California Cylinder Head component parts are all listed in this schematic.
Some items from this specific schematic: Bolt,flange Sh 6x, Screw,pan,5x20, Bolt,flange,6x32, O-ring,special.
In this schematic the "Washer,plain,8mm" is used most often.