I was thinking about this yet again on the road back home today.
It would seem that a 427 Z/28 would be likely at this point, given the "leaked" info on the 2014 models. The engine plus a suspension upgrade makes sense.
But what occurred to me is this:
COPO = Pro Drag
ZL1 = Street/Amateur/Enthusiast Drag
Z/28 = Pro Track Racing
SS 1LE = Street/Amateur/Enthusiast Track Racing
This makes sense to me and would match speculated price points. Having a naturally aspirated LS7 also makes sense to me for track racing. But the 1LE may also be a test bed for the Z/28 suspension and may disappear for 6th gen.