Set of 12 x chrome plated head nuts. Late Z1 type (picture centre) with height of 17.5mm. Unless you are fanatical about originality, I would use the later KZ type with greater height. Even better, the 72-342 billet head nut set. It’s really annoying to try and torque down the head and find that the dome nuts have bottomed out on the studs.
Models: 74-75 Z1