I thought they kept the 389 all the way up to 1970. They might have dropped it before they had to go for emissions control. I don't know all of what Pontiac had to offer, I am a Chevy guy. Back in the early 70's I got on a kick for Ford T birds. It was kinda of where my head was at back then. Luxury and performance was not a bad idea.If I'm correct 389 was available until 1966 , but I'm getting old & forgetful .But there was a early produced GTO w/ 389 option so nothing is set in stone . Just not sure if it was & option in a Bird . 389 was Pontiac's " Go To " motor for the big cars starting in the mid 50's " I think " .