Most power may not mean fastest though? Kind of a hard question to nail down.

When I think of brutal torque monster then maybe the Buick GSX is it. They are heavy though...

Max horsepower? LS6, or 6 pack and Hemi cars?

There are cars like 1971 351 Boss Mustangs that were faster than other cars with larger engines if you look at the old road tests. They are often overlooked, but still pretty quick.