Welcome to the Team Mike!
You are aware that only the "big" Chevy and the Corvette were allowed to have a motor bigger than 400 cubes that restricted the smaller cars to only a 396 SS. I would be thinking 427 SS in a '67 (only it would be a motor a lot bigger than a 427; as 496 cubes in big block is considered a good starting point today). But in terms of badges and decals it would say 427 TurboJet instead of a 396 that every one else has if I were cloning one.
The factory actually offered a 427 SS as a RPO package that was different from an Impala SS with a 427 motor under the hood, but they are extremely rare and have their own special hood that are not reproduced.