Delta 88 — H-body (1986–1991)

125 hp, the standard engine; Wikipedia's Oldsmobile 88 article prints it in its engine table for 1986 only and says 1986 was the only year with the 3.0 L; the 1986 NICB manual prints a 3.0L V6 MFI engine with VIN letter L but no RPO codes (matched by meaning only); shared H-body code, but the Buick LeSabre sources add no second source (gnttype.org prints LN7 only for the Somerset)

150 hp, the optional engine in 1986 and the only engine in 1987 and early 1988; Wikipedia's Oldsmobile 88 engine table is headed RPO/VIN code and prints "LG3/3" for 1986 to mid-1988 (the LN3 replaced it that year, so the two codes overlap in 1988), which pairs the code with a VIN digit and is not a slash form of two codes; shared H-body code, corroborated from the Buick LeSabre: gnttype.org's 1986 and 1987 Buick VIN tables each print engine option code LG3 for the LeSabre (one source, as the two blocks print the same engine cell); the 1986 NICB Oldsmobile engine table prints VIN letter B for the 3.8L V6 fuel-injected engine, where Wikipedia and gnttype.org give VIN 3 (the Buick figure)

165 hp; Wikipedia's Oldsmobile 88 text says the 3800 replaced the earlier 3.8 L for 1988, while its engine table dates the LN3 from mid-1988 (printed "LN3/C", the VIN letter C); shared H-body code, but no sibling source prints it: gnttype.org's VIN tables end at 1987 and the NICB manuals read print no RPO codes

Wikipedia's Oldsmobile 88 article says the 1990 model was left with the standard load-leveling suspension and the FE3 sport suspension (two alloy wheel designs) and that the FE3 option remained available for both Royale and Royale Brougham in 1991; the Ninety-Eight's merged doc words the same code "Suspension, sport, level 3"; matched to the car by the article's text, no list prints it