340/360 Z heads? Anyone know what Z heads are?

83-86 offered a 318 4-bbl to the law enforcement community. Besides having a Rochester 4-bbl, the engine had 1.88 intake and 1.60 exhaust valves. The valves resided in a head with a honking 75.1 cc combustion chamber (casting # 4323345). This is known as the "Cop Car" head.

I gotta pair of them on a 88 cop car motor.