"Base", as in less expensive?
Is there any money to really be saved by building a smaller-displacement version of, technically, the same engine? They'll have many similar parts...
I maintain the base Corvette engine and the Camaro V8 will be the same, as it is now, and has been in the past. Easy, smart way to save $$ through economies of scale...and it sounds as though this sub-Stingray Corvette has been debunked by everyone except these sources who are only "familiar with the plans"...
If there's a super Z28 in the gen 6...my crystal ball bets are on it sharing an engine with the future Z06...