I don't think the Boss motor is doing the BA Falcon XR8 too many favours in the performance stakes.
The 1/4 mile times for the Boss 260 equiped 2004 XR8 Ute which is rated at 260KW at the crank is 14.9
The 290KW Boss 290 powered BA Pursuit does 14.4 along with the new FPV-GT.
My 2002 XR8 Pursuit 250 ute shares virtually all the same running gear but uses the 250KW 347 Windsor motor. It turns the quater in 14.2
I think the extra weight in the front is probably the cause. All the road tests reckon the XR6 turbo is a much sweeter handling car because of the lighter front.
When the lease runs out on the Pursuit I think I'l replace the wifes Jag with an XR6 turbo.
There's 1/4 mile times for pretty much anything on the road here:
1/4 mile times
Cheers