There are some crazy deals on Z06's right now:
http://forums.corvetteforum.com/c6-c...n-33500-a.html (this one lists as sold but the buyer just put it back up for sale today, his wife apparently did not approve lol)
http://www.autotrader.com/cars-for-s...20735878&Log=0
Most of the stroker motors in the base model won't be a real LS7, it'll be a bored/stroked LS3 or something, so search for "stroker", 427, 402, etc. for the bigger cube motors. Those usually go for higher 20's though, and if you can pick up a Z06 for a few grand more it would be a better route to go.