The cam might be the Crane H-260-2, hydraulic flat tappet. Kinda mild: 204/216 duration at .050", .427/.454 lift, 112 LSA, and about 5 degrees ground in advance. This is a semi-torque/stump puller cam. It ought to jump out. Explains the mild idle and good compression readings.
Either plugged somewhere or really retarded cam as suggested.
If you lost a lobe, the shavings will generally go down into the crankcase and oil pan, then up into the pump and then into the filter. You might be OK, if the filters bypass never opened, but I certainly would replace the pump and pull it all apart to inspect everything. Hard to say exactly were the tiniest particles could go.
