Well if you tell a Dyno operator to make the numbers lie which isn't all that easy since most dynos have some set parameters for correction factors a dynos numbers are accurate as in what is printed off of the computer is what it actually has unless like you say "you can say your slant 6 has 550 HP" lol .
A Dyno is also not bench racing either it is a tuning tool to get every last bit out of an engine.
Dial in your air- fuel, dial in your timing, do testing, like figuring out what your engine likes for lash, everything you can test and get real data, compared to guessing or testing at the track where you might get 2 runs to see if a change made an improvement, I can't imagine buying a torque converter on a guess at $ 1000.00 or more. But if a engine like mine gets put in a **** car it still has what the dyno numbers say it's just in a **** car. It's not the dynos fault or lying
It's like guys who are hooked on flow bench numbers, put a head that flows 400cfm on some junk **** short block...it's not the heads fault or lying flow numbers.
I'm sure you already know all this though.
