Whats the stock hp of a 5.0 to the wheels?

IMHO, dynos are good for one session, multi-pull tuning. even the amount of strap ratcheting can make a difference - hence the one session theory. now compare different dynos and it gets crazy.

they are great for relative tuning, but not absolute.
my two cents.
 
I am sure condition of the engine has to do with it. Unless rebuilt or replaced all 5.0 mustang's engines are at least 9 years old and who know's how many miles.

Who cares about numbers, unless your a bench racer. I'd rather see accuracy. Like said before, it's a tuning tool, but some think it's a race track.