The out dated oiling system on my truck has been working satisfactorily for 67 years .
The noise you hear may be bearing related. The bearings , particularily mains, are shimed originally and it is not such a big job to pull a shim or two . requires patience and your workshop manual.
If your engine has not had regular , frequent oil changes through out its life , it may be due for overhaul if the noises you describe (lower end knocking and piston slap/tappet) really eminate from all those places.
