It was whatever the directions called for. Cant remember if its a whole or half a can. Ive also used iirc Gumout's Motor Flush. It wasnt on the vette but in a Mitsu Endeavor. That one you just idle it for a few minutes and it seems to clean things up pretty good. I dont use these products much but it was a higher mileage car and it did get quieter after. Sometimes you get lucky.

Ya Im with guy, worst case you destroy for cam bearings and cam, which are fucked anyways. Just enjoy it till it gets bad, then new bearings and a new cam.

Changed the oil to Rotell 15/40 and and put in some sea foam, but only have 20 miles or so on it. Sound is still there. Interestingly it's really only at partial loading, not all the time. Pretty quiet when idling, and doesn't seem to do it when romping (that i can hear). It's worst on a curve under light/partial load, like turning a corner.

Even the worse cam knock i've heard was still only under part throttle, i'm sure its happened, but I've never heard of catastrophic engine failure starting with cam knock

But would it apparently go away under WOT? My expectation would be for it to get progressively worse, but I guess it could be a more complex "resonance" type question.

Yup, light part throttle at idle, part throttle at cruise, no noise at idle or under WOT.