360 engine vibration

Don't fret over the crank bolt runout. Replace it with a new grade 8 if it bothers you, but make sure you keep the heavy washer. Final torque is in the range of 135 ft-lb, which is needed to tightly 'lock' the damper to the crank, so as to couple the crank vibrations into the damper.

BTW, does the damper just easily slip onto the crank snout? If so that is a problem. It should be an interference fit and should need to be pulled on or off. The 'true' surfaces that aligns the damper to the crank is the inner surface of the damper's hole, and the outer surface of the crank snout. The 'true' surface is NOT the back surface of the damper hub that contacts the crank sprocket (although it should be very close anyway).

If there is any looseness between damper hub and crank snout, then the damper inner diameter is damaged or the crank shout has been damaged. If it is the crank snout, then there are repair sleeves available. And, if either is loose, then any bend in the bolt or slight misalignment in the threading inside the crank snout would force the damper to go crooked when the bolt is tightened. So that could be the whole issue there.

Please take micrometer measurements on the crank snout OD in a few places and report for comparison.

BTW, nice thorough video and good narration! IMHO, you have worked this over pretty well.