I totally agree regarding noting the heritage of RPO ZR1. As an owner of an original 1970 ZR1 (with factory 4.56 posi no less), I interpret your comment, “…the light clickety-clack of that slight clearance at idle still makes my skin crawl” as a good thing, meaning you enjoy the sound of a high-revving mid-20th century Chevrolet small blocks. To me, the sound is nirvana.
I’ve owned a few Corvettes with hydraulic lifters (big and small block) and have floated the valves on all at about 6.5k RPM. At that point the car falls flat on it’s face (thankfully) before catastrophic damage is done. The 1970 solid lifter LT1 will keep revving until you stop, or it stops, and not in a good way… It’s buzz-saw moan is a sound to behold…
Chevrolet understood the risk of selling the ZR1 back in the day. The car came with a disclaimer “Not recommended for normal driving situations” as a way to dissuade John Q Public from buying the car - not to mention the fact that basic creature comforts like a radio or electric windows could not be ordered.
The unbridled potential the original ZR1’s performance package as offered back in 1970 was unparalleled in a street car, and today would never pass the muster of government regulation. So kudos to the new ZR1 as a torch-bearer. I can only hope it lives up to the promise that it’s great grand father made over four decades ago. And then some!