* Small-block V8s: These were the most common. Options included the 350 cubic inch (most popular), and 396 cubic inch. Horsepower varied considerably based on the specific configuration (carburetion, camshaft, etc.).
* Big-block V8s: These were more powerful, and optional. The most common big-block was the 454 cubic inch. Again, horsepower varied significantly based on configuration.
Therefore, you can't say *what* motor a 1969 Chevelle SS had without knowing the specific vehicle's options when it was built.
