As Ford transitioned to metric engine displacement designations at the end of the 1970s, the standard engine for the Marquis was a 4.9L V8 (the rebranded 302 V8, rounded up to 5.0L to distinguish it from the 4.9L I6); the Marquis shared this engine with the Cougar, Monarch, and Zephyr. The Marquis offered a 5.8L V8 (the 351 V8 from the Cougar XR7) as an option. For 1981, the engine line underwent a revision, with a 4.2L V8 becoming the standard engine on the base-trim Marquis outside of California.; the now-optional 5.0L V8 was offered on Brougham-trim Marquis and Grand Marquis four-door sedans. For 1982, the 5.8L V8 was dropped from the Marquis, with sales continuing in Canada. When introduced for 1979, both V8 engines were paired with a 3-speed SelectShift automatic. For 1980, the Marquis received the 4-speed AOD overdrive automatic transmission as standard equipment with the 4.2L V8 and was offered as an option with the 5.0L and 5.8L engines. For 1982, the AOD became the sole transmission for all three engines. Body design In conjunction with its downsizing, the 1979 redesign of the Ford and Mercury full-size lines transitioned towards increased parts commonality between the Mercury Marquis and its Ford LTD divisional counterpart. Along with sharing a common wheelbase, the two model lines shared nearly their entire bodyshell; many non-visible components were shared with the Lincoln Continental/Town Car and Continental Mark VI. The Marquis was offered in a two-door sedan (replacing the previous hardtop), four-door sedan (replacing the pillared hardtop sedan), and five-door station wagon (as a wood-trim Colony Park or body-color Marquis wagon); each body style used its own door design. Though sharing the same body as its Ford counterpart, the Marquis was externally distinguished by several styling elements carried over from the previous generation. While the LTD was styled with an egg-crate grille design, the Marquis received a vertically-oriented grille (similar to the 1978 Marquis and the 1980 Cougar XR7). The front parking lamps were styled similar to the 1975-1978 Marquis (hidden headlamps were abandoned in favor of quad rectangular headlamps); full-width taillamps (in contrast to the square taillamps of the LTD) returned, now bordering the license plate (relocated from the rear bumper). Instead of the rear vinyl roof used on LTD four-doors, the Marquis four-door was styled with a full-length vinyl roof (standard on all but base-trim examples, where it was an option). Similar