Good stuff Gordon!
That's almost exactly the same numbers my Clevo ran up on the dyno; 526.1HP and 467.6 FT/LBS.
Use the calculation of FWHP/1.36 (it'll be within +/- 5HP) to obtain your RWHP.
I got 388HP through my Toppie on a chassis dyno.
I would say you'll be just shy of 400...390 something.
It's enough for the street :evil3:
As i've never seen the XB, it'll be good to see it turn the tyres in anger real soon
Cheers,
Toby.