The Buick 430 would continue in use through the 1969 model year, and in 1970 both it and the 400 were replaced by a bored-out ...

1971-1973 Buick Centurion Even rarer than the Monte ... Also luring customers into the showroom was a 455-cubic-inch big-block V-8 good for 330 hp when the Riviera was ordered in GS trim.

There were 2,472 examples of the Stage 1 455-cube GS ... That’s better than the Buick’s 3.42:1. Still, the big-block GS455 also has a few extra horses and lb-ft tucked under the hood: 290 ...