to thump or not to thump?

Your detonation issues are the result of too much cylinder pressure because the cam is so small. If it was my car, I'd be look at the Crane 694561. Pushrod selection is crutial for proper preload, but it will run with stock rockers. Prob ought to upgrade the shafts tho, or simply upgrade to a set of mechanical rockers. But that's what I'd run in my own.