In the end, I think it's probably time to pull it out and take it apart slowly, unless you think another set of ears may recognize the problem
SCAT crank and rods often need off-size bearings, I generally see them being a little loose, but they can need more room sometimes too.
The .008 crank endplay is good, and my hunch is your cam endplay is good, but a shiny bearing in a fresh engine is not. In fact, most bearings look relatively unchanged after initial run, if yours is polishing up, there may be an issue.
Look close at the piston bosses, there were some SCAT cranks that could lightly hit the piston at BTDC, and after that, not much left to do but tear in and measure everything
Last comment, be completely sure it isn't an accessory or something, belt rubbing, bad PS pump, not saying you wouldn't recognize it, but just look real close before it comes out