My Challenge to U /6ers....

It not just the ricers who have more than one cam, more than 2 valves per cylinder, etc.. If there was a easy way to put a late model power plant under a classic hood,
I would do it even if it had to be front wheel drive. I think a lot of people would.
The yestermotor like a inline six with its long stroke might pull a school bus up a steep hill but it will never run with the modern passenger cars.

Quite obviously, you've never driven a twin turbo Supra. Even the non turbo models are not slow.