Z28 is the longest-running Camaro performance designation. On the third-gen platform it ran 1982–1986 with the LG4 / L69 / LU5 305 V8 family, then was replaced for 1985–1990 by the IROC-Z (B4Z RPO) when Chevrolet partnered with the International Race of Champions series. The Z28 designation returned for the 1991–92 model years on cars without the IROC association after Chevrolet lost the IROC name; some 1991 cars carry both Z28 and the IROC-Z option-block legacy depending on build sequence.
Designer — Jerry Palmer was chief stylist of the Chevrolet Studio that produced the third-generation Camaro. Palmer's other credits at GM Design include the 1984 C4 Corvette (over which he had primary studio responsibility) and the 1993 fourth-generation Camaro that followed this platform; he later became Vice President of Design at GM. Aerodynamic refinement of the third-gen body was conducted in GM's wind-tunnel facilities. Irv Rybicki — VP of Design at GM 1977 to 1986 — provided the corporate oversight that approved the third-gen's lower nose and pop-up headlights.
Plenum decodes the Z28 RPO from the option block; on cars where Z28 and B4Z appear together, the build-date overlay disambiguates which trim applies.