There were only a few 1978 & newer A/G bodies that got an engine larger than a 305 Chev. The 350 Chev was an option in the El Camino in '78 & '79, and I believe in 1980 as well (I'm sure that another member here can clarify that). The 350 Olds was available in the
Hurst Olds in '79 and I think in 1980 as well, but not in a regular Cutlass. There were some police package Malibus built in the early '80s, and I believe that the 350 Chev was available in them. And then, as always, the 350 Olds diesel was available in the Cutlass from '78 into 1980 and maybe further. I actually found a 1980 Cutlass coupe for sale last year with the 350 diesel in it. As far as I know, in the late '70s, Buick was promoting their early turbo 3.8 engines in the Century & Regal, as their top of the line performance engine, as opposed to using a V8 in those cars. The smaller Olds V8, the 260, was available in the Cutlass from '78 (there was a factory option of a 260 Olds V8 with a 5 speed manual gearbox in '78) up until 1980 at least. As I said, I'm sure that there are other members here who can clarify this a bit more. Hope this helps.