There are no bearings in the top end, but you can wipe out cam journals and lobes. Depending upon the failure, maybe the head was starved first and you got away with it. As for the bottom end, we are talking crank and rod bearings. Possibly pins. It all depends and you won't know until you do a bit of tear down.

It will also depend upon the failure. Sudden or chronic (i.e., high enough to work, but not enough to really supply the engine, finally ending in complete failure). Either way, it is not pretty.

Good Luck,
Michael