TDR's (ex)car is a bit unusual because it is an auto with a high-stall torque converter, so it gets off the line much quicker and therefore gets into its stride earlier which means it makes a better ¼mile top speed and time than its power would otherwise achieve.
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As for the rest of the thread; we've been here before...
Scene One: Dyno Operator gives his satisfied customer an optimistic flywheel power figure.
Scene Two: Customer starts quoting this figure to all and sundry, but now claims it as rwhp (making the original inflated-a-bit figure truly ridiculous.)
Scene Three: Forum bunfight ensues.
If it has the stock 440cc injectors and FPR, Billy Bhoy's car cannot make 447hp@Flywheel. It is physically impossible for a 6 cylinder turbo engine to make more than 415hp with this fuelling setup because 440cc/min injectors cannot flow enough fuel to make >415hp.
Of course, people always believe that their car is "a good'un" and/or that it was mysteriously tweaked to some unknown spec by a previous owner - which is apparently why it can bend the laws of physics and is able to extract significantly more power from the injected fuel than is mathematically possible.
But Hey, who cares? Just enjoy the car and its power. It's been running this setup for several years without an issue. So it seems to be running OK.
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ps,
IMO ¼ miles times are not a good indicator of power but ¼ top speed is. (I believe TDR and many others agree). Good ¼ times are very dependant on the 60' times, the top speed less so.