[TJ's GMC]

Judging by the wear on the notch of the bearing I'd say it spun. It is pretty scarred up. Luckily you caught it quickly. Pull All of the caps off and check them over. Thing is if ran with low oil that can cause major problems. 1 quart low isn't bad, but much more and you can had issues. Just cause one was knocking doesn't many any others aren't going to or are far behind. I'd be checking the whole bottom end over. Pulling the mains and rod caps and checking all bearings. You have the motor Out and Apart so why not? Bearings are "cheap" insurance. I'd also have the crank checked over, mainly that one journal where the bearing went south. You may have to have over size bearings installed on that one. My 305 didn't have a knock but the bearings where worn down. So a standard set was fine, but slight damage needs to be ground out and may not be visible to the eye.