A "1080" kit was really like 1060 or something. You can achieve 1080 with stock stroke anda stock block. Here's what it would look like:
Yeah, the cylinder liners are almost touching and really thin. The only way to run a 1080 without head-gasket problems is to fly-cut a relief into the head and run a copper/piano-wire headgasket. It can be run *reasonably* reliably with a headgasket like that, but you'll get base gasket leaks off and on. You'll need additional vents for the crankcase/head to keep from blowing oil seals out (much more piston mass=more displaced air per stroke). You'd need MUCH stronger rods to run it, but with some good rods you could twist that motor to 11k. Heat is an issue.
The "Cobra" motors were available even larger than 1080 I believe. The RC Big Block was a set of jugs with "RC" cast into the sides. It wasn't a plaque. The jugs had really short fins and no air-passages. They also had larger gasket surfaces top and bottom to allow better gasket sealing.
Now, there was one interesting thing in the auction. Carpys mentioned the valve-cover being raised to allow for a really big cam. Any truth to that? I've never heard of that being necessary before, and I can't tell if it's been done or not. If someone went to that much work (raising the valve cover and bolting the cam towers through it) it might very well be a 1080. But from the pics I received I wasn't willing to make the 250mile each way drive to see it when it was on Craigslist. Carpy does know his motors, however, and he isn't one to outright lie. If he's saying it's a 1080, and he has the bike in front of him, it may very well be.
