Rob, to be fair, I was laughing about that a bit. I mean, some of the cars of the late 60’s and early 70’s had as much as 475 horsepower, showroom stock, if you can believe it. As an example, the Yenko Camaro, which came with a Chevy 427, put out 450 horsepower and 460 lb-ft of torque. So while MOST of those rides didn’t have 400 horsepower, some definitely did.
Heck, even the Boss 302, although rated at 290 horsepower, was capable of much more, and that’s just a little 5.0L engine.
With a bit of tuning and dual quads, that same engine routinely put out a verifiable 470 horsepower. They raced them that way.
Detroit routinely lied about actual horsepower numbers in that era, or at least told half-truths. They’d list a horsepower at a given RPM that was sometimes a couple thousand short of peak HP.
So your 335 horsepower Cobrajet for example? Yeah. Not really. =) Big-block cars of that era were called ‘musclecars’ for a reason!