Unfortunately, I think the headline of this article pretty much accurately sums up the situation.
http://www.motortrend.com/news/2018-...z28-successor/
At this point I don't see GM making an LS7 type N/A engine again.
Unless they drop in the LT5, going against the Z/28 is N/A philosophy, into the ZL1 1LE, or put the LT1 in the ZL1 1LE chassis, which I don't see either happening, Z/28 is probably going to skip this generation.