I did do a search... perhaps user error but did not find anything relevant to XKR's - 5.0 specifically.

Has anyone put a stock (or modified) XKR on the dyno? What are the real world rear wheel numbers?

 

You can find dynos for that same engine in the XF and XJ forums. Stock whp on a Dynojet seem to come in around 420ish, and 470ish with the ETG tune...a little more if you do other mods.

Bruce

 

Unfortunately due to my schedule I didn't dyno mine prior to the 3Lbs pulley, ECU tune, and exhaust so I don't have a baseline. I will be taking it to a shop that has a dynojet in the coming weeks and will post those results.

 

Youtube has 413RWHP:
To 4,208RWHP...WOW!(I know I know it's a typo..LOL...428RWHP):

 

I have an appointment at Eurocharged Houston to do before and after dynos this Friday afternoon. I am doing the tune and pulley upgrade. I will document the process and create a thread complete with pics and dyno charts. I am hoping for some great gains and look forward to sharing the results.