Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com

The best answer that I found came from a random forum post. Normally I wouldn't think that is much of a source, but you randomly asked in a forum... :)

Quote:

The Regal was a bit more "sport oriented" than the Century. The Regal had the 3800 V6 as standard and the supercharged 3800 optional whereas the Century had the 3100. Also, differences included stiffer suspension and bucket seats in the Regal. A basic Regal is basically a Century with more guts and bucket seats.

It does seem odd that one brand would have two identical cars, but GM, Ford and Chrysler have been making billions doing this exact thing for decades. Welcome to the world of badge engineering. In fact, if you're looking at the Century/Regal, why not check out the Chevy Impala, Chevy Monte Carlo, Pontiac Grand Prix, and Olds Intrigue too as they're all basically the same car again.

Gm eventually realized their stupidity and consolidated Buick heavily. The Century and Regal were dropped for the Lacrosse, the Rendezvous and Rainier were dropped for the Enclave and the Lesabre and Park Avenue were dropped for the Lucerne. Now, of course, GM has retrenched on their earlier commitment and has re-introduced the Regal. At least they're different cars, even if they are in the same size class.

https://buickforums.com/forums/threa...78/#post-76338

They had the same chassis and body?!