Wow! Never seen that before. I know this isn't the same thing, but I rebuilt a '39 Ford 9n tractor/bucket loader with my friend/part time boss this summer that he got for $600. Someone had the engine rebuilt (and clearly didn't want to spend too much on having it rebuilt) so whoever did it had the IQ equivalent to a 5 year old and put bearings in wrong, horrible wiring jumpering, oil pump rebuild wasn't done right, rod cap bolts over-torqued, etc. So most of what our time was spent on was fixing all the damage the previous owner had done. I guess he was using it and it spun a bearing because the oil pump had been rebuilt poorly and when we took off the oil pan it was full of sludge (cleaning it out was one of my jobs...oh joy). We did a total engine rebuild: all new lifters, guides, seats and valves, new bearings, the piston rings, honed the cylinder walls (and used hydrochloric acid w/ emery cloth to clean and fix the piston #1 bearing surface (spun bearing) and all new gaskets, water pump rebuilt, redid the electrics and added lights (correctly) new starter and alternator, new distributor, coil, plugs and points and rebuilt the oil pump correctly this time. It's such a cool little tractor. 4cyl flathead engine is REALLY torquey and it does look pretty poor, but I like that. Everything (including the original hydraulics - just topped off with oil) works fine and it runs perfectly! Really quiet, and I like that when you look at it from the outside it looks beat up and like it is just scrap, but it performs and runs like new. I like that whole "humble" factor.
Sorry, this really didn't pertain at ALL to your post except for the oil pump bit. haha
- '91 Saab c900 N/A base model