[v8volvo]

As ngoma suggested, you don't want to run the engine again until careful inspection. These are weird symptoms and hard to guess the cause, but some possibilities involve the timing system and if that is involved and something is coming loose, the damage could get a lot worse.

Bluish-white smoke in some instances can be from poorly combusted fuel, it might not necessarily be oil. The fact that the sound and smoke output of the engine instantly changed after the "clunk" is a classic scenario of slipped timing, which could be a timing belt jumping a tooth, a tensioner falling out of position, crankshaft timing gear slipping / keyway rounding, etc. Timing belt tension, cam and IP timing, and CRANKSHAFT BOLT TORQUE all need to be confirmed perfect before starting it again. Then move on to other possibilities once you know the engine is not about to self-destruct.

Also maybe we should back up a minute so that we get the whole story. In another thread you were working on figuring out major difficulty with starting. After the mechanic's recent adjustments leading up to when you got the truck back this time, was that previous problem fixed? Started quickly and cleanly, no struggle or long cranking or rough idle after startup? You say runs and idles good. But is that all the time or only after it warms up?

AND, if the other problem was solved, what were the specific adjustments that were made in connection with that? Adjustments to the fuel pump itself? Timing adjustments? Can you get more exact detail from your mechanic on this? It could be that something they recently changed during that attempt is to blame for the new episode now.