What was the first year the 350 Chevy engine was used?

The 350 engine was first used in the 1967Camaros, Novas, and Chevelles. It was 295hp. I believe it was used in all of the Chevy models the following year, 1968. The hp. increased each year til 1970, then started going back down again in 1971, due to lower compressions and emission control equipment.