Body insulation package

Years 1963–79 Models 3

Also described as Insulation Package (Monte Carlo only?)

Documented applications

Chevelle / El Camino

1972 Confirmed

Impala / Full-Size

1963–70s (varies) Confirmed

Monte Carlo

1972 Confirmed

"Monte Carlo only?" per source

This page aggregates every documented appearance of ZK1 in the Chevrolet reference. Confidence and citations are shown per application — the same code can be better documented in one year than another.