Hmm, just recently checked. They’re still running the tried, tested, and true AMG V12 powerplant, it’s done wonders so I can’t see why they’d ditch it. Some background on the V12 AMG engine, it was originally used the Mercedes CLK GTR.
Although the later versions coming out, sometime in 2010 will stick with the Mercedes motors, AMG style like from Mclaren SLR 722 or maybe the Mercedes bi-turbo V12 :o
http://www.carzi.com/2008/08/06/2010-pagani-zonda-f-spy-photos-no-camouflage/