Buick Skylark — X-body, front-drive (fifth generation) (1983–1985)

The fifth-generation Skylark was Buick's front-drive X-body compact: Wikipedia gives a two-door coupe and four-door sedan, the Custom trim from 1983, the T-Type (a coupe only) in place of the Sport, and a sedan-only 1985 in Custom or Limited trim. The NICB VIN manuals list the Skylark, Limited and Sport for 1983 and the Custom and Limited for 1984–1985. No GM order guide, data book, Heritage kit or service RPO list for the Skylark is in the archive, so only powertrain codes are listed: Wikipedia's Skylark article names the engine codes and gnttype.org's 1984 Buick VIN table prints them for the Skylark, and the Heritage kit pages of the Chevrolet Citation, the X-body twin, are cited only to date the engine codes the two cars share and for the automatic-transmission codes, which no Skylark source prints. No source read ties an option, package, paint or trim code to the Skylark with a year, so none is listed.

Codes

Engines

Code	Description	Years	Models/Notes	Confidence
LR8	Engine, 2.5 L (151 cu in) L4, throttle-body fuel injection	1983–1985	the standard four-cylinder; Wikipedia's Skylark article names LR8 in its fifth-generation infobox and gives the Iron Duke four to 1985; gnttype.org's 1984 Buick VIN table prints it for the Skylark (VIN R), a second source (owner ruling, 2026-11-05: a T3 page that names the code for the nameplate, with Wikipedia dating every year); shared X-body code; cited from the Chevrolet Citation kit, whose engine pages print it with its model year ⛭ GM Heritage — 1983 Chevrolet Citation, p.10 ⛭ GM Heritage — 1984 Chevrolet Citation, p.10 ⛭ GM Heritage — 1985 Chevrolet Citation, p.7	confirmed
LE2	Engine, 2.8 L (173 cu in) V6, 2-barrel carburetor	1983–1985	the optional V6; Wikipedia's Skylark article names LE2 in its infobox and gives it to 1985; gnttype.org's 1984 Buick VIN table prints it for the Skylark (VIN X), a second source (owner ruling, 2026-11-05: a T3 page that names the code for the nameplate, with Wikipedia dating every year); shared X-body code; cited from the Chevrolet Citation kit ⛭ GM Heritage — 1983 Chevrolet Citation, p.10 ⛭ GM Heritage — 1984 Chevrolet Citation, p.10 ⛭ GM Heritage — 1985 Chevrolet Citation, p.7	confirmed
LH7	Engine, 2.8 L (173 cu in) V6, high output, 2-barrel carburetor	1983–1984	the T-Type's standard engine in Wikipedia's Skylark article; Wikipedia names LH7 in its infobox; gnttype.org's 1984 Buick VIN table prints it for the Skylark (VIN Z), a second source (owner ruling, 2026-11-05: a T3 page that names the code for the nameplate, with Wikipedia dating every year); 1985 is left out of the Years because the Citation kit's 1985 engine page lists the multiport-injected LB6 in its place, although Wikipedia's engine list runs LH7 to 1985 (see gaps); shared X-body code; cited from the Chevrolet Citation kit ⛭ GM Heritage — 1983 Chevrolet Citation, p.10 ⛭ GM Heritage — 1984 Chevrolet Citation, p.10	confirmed

Transmissions

Code	Description	Years	Models/Notes	Confidence
MD9	Automatic transaxle, 3 speed (THM 125)	1984–1985	GM engineering code behind the MX1 merchandising option; matched to the Skylark's unit by meaning: Wikipedia's Skylark article names the 3 speed Turbo-Hydramatic 125 automatic in its infobox but prints no code; the Citation kit's automatic-transmission weight line for the 2.5 L engine reads "Merchandising Option for MD9, MX1"; 1983 is left out because no listed kit page heads the code that year; shared X-body code; cited from the Chevrolet Citation kit ⛭ GM Heritage — 1984 Chevrolet Citation, p.34 ⛭ GM Heritage — 1985 Chevrolet Citation, p.33	single-source
MX1	Automatic transmission, 3 speed (merchandising code for the THM 125)	1984–1985	matched to the unit by meaning: Wikipedia's Skylark article names the 3 speed Turbo-Hydramatic 125 automatic in its infobox but prints no code; the pages print MXI (letter I); 1983 is left out because no listed kit page heads the code that year; shared X-body code; cited from the Chevrolet Citation kit ⛭ GM Heritage — 1984 Chevrolet Citation, p.34 ⛭ GM Heritage — 1985 Chevrolet Citation, p.33	single-source

Sources

Factory documents (T1)

No Buick factory document for the 1983–1985 Skylark is in docs/factory-docs/ or docs/heritage-ocr/. The rows cite the Chevrolet Citation Heritage kits (X-body twin) for shared engine and transmission codes only, on the brief's listed RPO pages (owner, 2026-10-03):

[HK] chevrolet/1983-Chevrolet-Citation.txt — MVMA specifications, 1983, engine description page (p. 10)
[HK] chevrolet/1984-Chevrolet-Citation.txt — MVMA specifications, 1984, engine description page (p. 10) and optional equipment weights (p. 34)
[HK] chevrolet/1985-Chevrolet-Citation.txt — MVMA specifications, 1985, engine description page (p. 7) and optional equipment weights (p. 33)

Other sources

https://en.wikipedia.org/wiki/Buick_Skylark — fifth-generation infobox, body styles, trims, production table and engine list (retrieved 2026-11-05 as wikitext, action=raw)
http://www.gnttype.org/general/vin.html — per-year Buick VIN decoding tables with each Skylark engine's RPO code (retrieved 2026-11-05); the tier verification covered only the site's Regal RPO list, the owner ruled on 2026-11-05 that this page counts as a T3 second source for the codes it prints. Its 1983 table is the 1984 table with the header changed, and its 1985 Skylark block is the N-body car, so only the 1984 table is cited.
NICB Passenger Vehicle Identification Manual, GM sections (T4): docs/reference/nicb/nicb1983-gm.txt pp.26–28 and nicb1985-gm.txt pp.27–28, read on the page images — Skylark series names and engine VIN letters