Above 5-7" of vacuum your crank seals leak vacuum on both the damper and the output side... That makes it hard to get to the vacuum needed to cavitate the pump.

The suction side of the pump can cavitate, but I dont think thats what happened.

That looks like some serion starvation, most likely the crank is toasted and has heat dammage.

The block may not look very happy either if it looks like the saddle.

Kevin

87 Turbo Intercooled Raider, roller cam, torsen rear diff, LSD front diff, lockup auto with modified converter, V6 brakes, low transfer case gears...