The document in question is an internal memorandum of understanding between General Motors, the UAW and Delphi. The result of negotiations that took place back in June 2007, the document details future product commitments to which GM had agreed, one of which is a new 'Gen V' 6.2L DOHC V8 engine for use in the C3XX platform. As we learned from the most recent negotiations between GM and the UAW, C3XX is the codename for what will replace the GMT 900 platform that underpins the automaker's current line of full-size trucks and SUVs.
In addition to a new overhead valve design, the Gen V engine will also feature variable valve timing like the Gen IV engine it replaces. Since the new engine will likely have four valves per cylinder because of its OHC design, expect the VVT to be even more beneficial. In addition, and perhaps most surprising, is that the Gen V will also feature GM's active fuel management (AFM) or cylinder deactivation technology. This technology alone will give it the leg up on other OHC engines like the Toyota Tundra's 5.7L DOHC V8.
Mike Levine from Pickuptruck.com who discovered this revealing document also reports that GM's current 5.3L V8 will be replaced by a new engine of unknown displacement. Unlike it's big brother, however, this next-gen engine will remain an overhead valve pushrod.