back in the 60's and 70's each car had its own engine. most of them over a 318 made decent power.
my 70 formula 400 had a 350 HP 400 in it. stock rating.
once you get to that G6 its a Chevy engine under the hood, it was the 80's when they all lost their own engines and used just Chevy engines.
kinda makes sense, why make 4 gm brands of cars and have different engines, saves a lot of money being the Chevy engine was by far the best one.
I hear ya but I really didn't Care about sharing engines the sport styling was attractive to me. My Dad drove a couple SSEI bonnies I've owned a couple vibes and Grand Prixs and always liked Pontiacs. Life goes on though. lol