Finally! The hood scoops on the 1969 were finally functional, adding about 8% more horsepower. However, Buick left the engine spec ratings the same as the previous year. Performance increased on the option packages, the Stage 1 and the very rare Stage 2. With the changes, sales dropped in half this model year, and the GS would go through some big changes for the 1970 model year.
1969 Buick GS 350
The car really didn't change much this model year from the 1968 Buick GS. The engine stayed the same, the only thing affecting performance was the working air scoops.
1969 Buick GS 400
The GS 400 engine didn't change at all for 1969 either. The real changes came with the two performance options, the Stage and Stage 2.
This option added 5 more horsepower over the standard 400 engine, by increasing the compression ratio to 11.0", using a high lift cam, and a different exhaust system. It also included special coding under the hood.
An even hotter cam was used with this option to create 360 horsepower. This was a very rare option sold.