Misfire at cruise, popping/afterfire at 3000RPM

IF that's even your problem.
Yes, hydraulic cam.

Agreed, that's assuming that's even the problem. And quite honestly, if I end up digging into the engine again for troubleshooting, I'd probably just rebuild the damn thing. It really bugs me not knowing any of the specs of the build or what it looks like inside. And although I'm obviously not an expert engine builder, when I built my 318, I had great peace of mind knowing what went into it, because I did it myself.