MP billet stands, hard chromed shafts. The spec rocker is the MP stock replacement style but there have actually been several types used over time depending on availability, because of the push to clean up backorders. Lesson learned: substituting is better than waiting for parts to show up for 6 months. If you wait for parts, you're in the hole before you know it so don't wait.

IIRC Barton told me something like 80 or 100HP is a cam swap away and I don't doubt that, but the 528 is supposed to be a conservatively built, streetable MP crate motor...Not a race motor though many of them run in the 10s (never mind the guy who can do a wheelie in the driveway)....so the cam swap would be up to the end user....you couldn't (for example) order a crate motor with your choice of parts in it....

Since getting blocks/heads/rockers/rocker stands is no problem anymore, and since real race engine builders are now working with MP there's a pretty decent possibility for more radical crate motor combinations in the future, but they are strictly in the idea stage.

I've heard some important folks talking about a high compression, maybe roller lifter, maybe larger CI deal at some point in the future but AFAIK no testing of a combination like that has happened, and no program of that type exists right now.