The Corvette hasn't had a DOHC powerplant since Clinton's first term, and while the LT5 was a pretty awe-inspiring mill in the day, it's handily destroyed by today's LS7 and is matched by the 'Vette's base motor. However, a document posted on the DigitalCorvettes forums may point to the fact that the LS9 will indeed ditch the pushrods and put the cams over the valves. Then again, it could all be a buncha hooey.
[LS9 DOHC info?] I have something to show you [Digital Corvettes]
The Forums Are Aflame With the Whine of Blowers: Corvette SS Rumors? [Internal]