Older small block and big block chevs ran a press in
oil pump pickup. these could come loose with bad results. The standard practice was to tack weld them to the
oil pump once in place.
Was the picup hitting the bottom or side of the sump? Something enought to cause some leverage on that weld?
It looks like the whole pickup is just supported off that pipe. It may be worth welding a tab to the pickup and running the tab to one of the
oil pump pickup flange bolts for extra support.
Cheers