Lots of opinions here but it's fair to say you're faced with a few issues;

Engine has a lot of miles on it. I suspect the new oil pump may have gotten you further down the road, but chances are good the mains are pretty well worn out.

The path of oiling can make or break you in a situation like this. With loose clearances you're losing control of the oil along the way. Everything further down the path of the oiling system gets progressively less oil, which means more wear, higher temps, etc.

Some engines will indeed run a long time with worn out bearings and/or low oil pressure, but others won't. I've run small block Chevy's with the gauge bouncing off zero for miles and have an AMC 360 with all the mains well into copper and yet it runs fine. I've had poly 318's go a long time but not had as much success with LA engines. Perhaps it's all a matter of chance.

I'd think you'd be getting some lifter noise by now.

Regardless, it seems like you're at the point where reliability of the car is a real concern. If you're like me, the last thing you want to have happen is a breakdown somewhere on the highway, or worse yet out in the country and be stuck there, having to leave your car to go get help.

By the way I've a 67 Fury III 4dr hardtop too and love the car. Have had it for years. Great running/driving car and it's tough to have any 4 dr look as good as these do.