True, there were, toward the end of the late '60s-early '70s hp-wars, some under-reporting of hp for insurance purposes... BUT, remember that the method of measuring hp/tq was different back then, as well (done without any accessories, etc.), and thus WERE higher than what would be reported today with the identical engine, apart from any marketing shennanigans.

I am an antique engine fan (racing an 1100hp, 299c.i. twin-turbo "orphan and having a couple 392 hemis), but that doesn't change the fact (i.e., the reality) of the near "magic" that can be done with today's flow development, along with current electronic engine-control systems. There simply is no other way we could maximize all performance perameters, nearly simultaneously, to max power, emissions, and gas mileage. My co-daily driver (with the new hemi-Ram) is a C-5 Vette. It is a legitimate 175mph street car that will do 0-60 in 4.7 sec. while meeting emission specs and averaging a genuine (fillup to fillup--not computer monitored) 31mpg at a constant 72mph all day long! Ain't no 426 hemi that would ever do that, even in as slick a body.

Technology is simply amazingly great... when it works!

All the best.