Fleetwood — C-body front-drive (1985–1992)

the HT-4100 (High Technology) V8; Wikipedia's High Technology engine article gives the option code LT8 to the HT-4100 and lists the Fleetwood among its applications for 1985–1987, and its Fleetwood article names the HT-4100 as the engine until it was replaced for 1988; the Wikipedia articles are one source, and the code is not printed in a Fleetwood-specific factory page; the DeVille, Eldorado and Seville share the engine (sibling and platform mates, corroborating the code only); decoderpo.com (T3, undated, no vehicle) reads LT8 as a 4.1L V8 engine, agreeing on the meaning only; single-source

Wikipedia's Oldsmobile diesel engine article lists the 1985 Cadillac Fleetwood among the applications of the front-drive LS2 (with the Buick Electra, Cadillac de Ville and Oldsmobile Ninety-Eight), and its Fleetwood article lists the 4.3L LS2 diesel V6 in the front-drive engine list and table; decoderpo.com's LS2 entry reads as a 6.0L V8, a different meaning, so it gives no support; the Wikipedia articles are one source; single-source

Wikipedia's High Technology engine article heads the 4.9 section with the code L26 and lists the Fleetwood among its applications for 1991–1992, and its Fleetwood article says the displacement rose to 4.9L for 1991; decoderpo.com (T3, undated, no vehicle) reads L26 as a 4.9L V8 with multiport fuel injection, agreeing on the meaning only; the Wikipedia articles are one source; single-source