It's all in how well they are/were maintained, my olds 350 has somewhere around 60K on it, (speedo is way off so it could be much more) I have had it since it had about 3000 miles on it, and my oil is always nice and clean when I change it (usually between 2000-2500 miles, or 3 months, whichever comes first). Any neglected engine will gunk up and get nasty, the worst one I have seen was a sbc that someone had over heated who knows how many times and never bothered changing the oil, when I pulled the valve cover off, the sludge in that engine was built up over the entire valve train (you could barely see the rockers) :shock: . So it's all in the life the engine has lived, if abused of neglected (which it seems the engines you have found are), any make engine will/can gunk or sludge itselft to death.
As far as the oiling problem, which isn't getting the oil to the top, but rather getting it back to the bottom. Olds' engines can pump the pan dry if used at high rpm for extended periods, so there's a few things you can do. The easiest thing to do is make sure the drain holes in the heads don't have any burrs on them, if so knock it down, you can clean it up a bit there as well making sure the path is clear from obstruction. Some builders say to put retrictors in the upper end to limit the amount of oil that gets pumped to the top, and to enlarge the oil hole it the main bearings (unecessary unless you're building a race engine that has to live 6500+ r's). Then you get into the oil draining down on the rotating assembly an being thrown about the crankcase, so there's scrapers and trays for this problem, again on a purely street engine where you'll be staying around 2500 rpm, this is a non issue. One the modifications that I had seen a while back was from mondello (I think), what he did was create an alternate path for the oil to flow, drilled and tapped holes in the backside of the heads (as low as possible), installed fittings and ran hose down directly to the pan to limit crank interference. Not sure how this method worked out, but I do like the theory, and when I have time to do more research on it, I may use that method when I build my 455. If the engine is used for it's original purpose (lugging around a 5000 pound car across country) the stock oil system is plenty sufficient, if used for street/strip, do a little research with an Oldsmobile specific builder (Dick Miller, Mondello, BTR, Rocket Racing, etc) to find out what really has to be done for your specific application. Good luck.
As far as the oiling problem, which isn't getting the oil to the top, but rather getting it back to the bottom. Olds' engines can pump the pan dry if used at high rpm for extended periods, so there's a few things you can do. The easiest thing to do is make sure the drain holes in the heads don't have any burrs on them, if so knock it down, you can clean it up a bit there as well making sure the path is clear from obstruction. Some builders say to put retrictors in the upper end to limit the amount of oil that gets pumped to the top, and to enlarge the oil hole it the main bearings (unecessary unless you're building a race engine that has to live 6500+ r's). Then you get into the oil draining down on the rotating assembly an being thrown about the crankcase, so there's scrapers and trays for this problem, again on a purely street engine where you'll be staying around 2500 rpm, this is a non issue. One the modifications that I had seen a while back was from mondello (I think), what he did was create an alternate path for the oil to flow, drilled and tapped holes in the backside of the heads (as low as possible), installed fittings and ran hose down directly to the pan to limit crank interference. Not sure how this method worked out, but I do like the theory, and when I have time to do more research on it, I may use that method when I build my 455. If the engine is used for it's original purpose (lugging around a 5000 pound car across country) the stock oil system is plenty sufficient, if used for street/strip, do a little research with an Oldsmobile specific builder (Dick Miller, Mondello, BTR, Rocket Racing, etc) to find out what really has to be done for your specific application. Good luck.
