One new cylinder head cam tower shim kit (Head Saver kit that shims the cam tower back to factory OE stock cylinder head thickness), part number 11042-U0100.  These fit:

• Datsun 240Z 1970 - 1973 (uses two kits-purchase of two is required)
• Datsun 260Z 1974 - 1975 (uses two kits-purchase of two is required)
• Datsun 280Z & 280ZX  up to 1983 (uses two kits-purchase of two is required)
• Datsun 510 L16 & L20 1963 - 1979 (uses one kit)
• Datsun 610 L18 & L20 1972 - 1976 (uses one kit)
• Datsun 710 L18 & L20 1974 - 1977 (uses one kit)
• Datsun 521 L16 1969 - 1972 (uses one kit)