[MAURICE BLENDHEIM]

Early 1967 Z/28 cylinder heads were "462", Late '67 castings were "291" with no temp sender provision. Early 1968 Z/28 heads were "291" with introduction of temp sender and late 1968 castings were "186". Screw in studs and guide plates ONLY came on Performance Optioned small block engines with factory installed 2.02 & 1.6 valves. All the above mentioned heads were also available with 1.94 &1.5 valves and came with NO factory installed screw in studs and guide plates, "291's" may have an un-drilled lug for temp sender. The 1967 Z/28 connecting rods (3864881) were a regular production rod, that utilized a press pin. The floating pin was a late 1968 Z/28 introduction. Hope this helps... MB.