Speakers, extended range, dual rear

Years 1987 Models 1 Factory citations 1

Also documented for Cadillac Chevrolet GMC

Documented applications

Regal — G-body (1983–1987)

1987 Factory-verified

not with U63; included with UM6, UM7 and UX1; gnttype.org's 1987 option sheet; shared G-body code, cited from the Monte Carlo kit

GM Heritage factory kit — 1987 Chevrolet Monte Carlo, p.40.

This page aggregates every documented appearance of U66 in the Buick reference. Confidence and citations are shown per application — the same code can be better documented in one year than another.