Hard to believe this would be the cause after all these years, but if a new/old stock pump was just installed?... or if something moved or got into the pump to cause the blockage?
The oil pump is positive displacement so anything blocking the pump on the discharge side will make something pop apart or burst. We're you riding or just testing at the house? The whole time that engine was running it wasn't getting any oil.
testing at the house. also had some oil mixed in the gas. but sad but that's why the first engine blew. friends sled and not sure who put that line on.
Aftermarket (improper fitting) line would be my guess. The right line uses OEM clamps and stays secure. Zip ties on fuel/oil lines make lots of money for the parts man. They should never be used.
Unless there is something plugged in the fuel pump or the line from the oil pump, most likely that check valve was in backwards. Did a professional rebuild it the first time? I would be pounding down his door over that.