Oldsmobile came out with their 455 in 1968 Buick and Pontiac released their 455s in 1970 Chevrolet 454 was 1970, also
JS
Just a reminder there was prohibitions on certain GM products over 400 CID for a few years. When GM saw the EPA writing on the wall they dropped it around 1970.
They got around it for a bit by having third parties install 400+ CID engines after the sale for a few years before that, Yenko Chevrolet maybe?
