Regarding emissions certification.
If the Z28 is having difficulties passing current standards, would the in place technology for the C7 not be readily be available (it would require a modification of the cylinder head casting to include direct injection)?
I can imagine with the huge ports; intake velocity is too low at idle to fully atomize fuel with a port injection set up.
Direct injection and variable valve timing will clean up idle emissions (they do it for 9000-rpm Ferrari and Porsche).
As you all know; valve/port sizing and cam timing optimized for producing power at high rpm will compromise low speed running or idle, hence all super car manufacturers have the direct injection and variable valve timing in their tool box