Just something to check for piece of mind. Did your machine shop put the correct galley plugs in or maybe forgot to put anything in the distributor galleys? These are the small plug with something like a .40 thousands hole in them to oil the distributor gear. If left out you will have very low oil pressure and the upper end will be dry, common mistake by those who do not know Oldsmobile's .

As stated above first generation Oldsmobile's don't sling much oil at all compared to it's Chevy brothers..... Tedd

 

Evidently the stems get enough . They have umbrellas on them to prevent them from getting too much .

Did you disassemble the rockers and shafts and inspect for wear , when you did the overhaul ?
A rocker shaft that is clogged with sludge will slow down oil flow too .
New shafts are a good idea when you overhaul anyway , because you eliminate the dirt and sludge that may be there . Rocker arms that are worn more than .002 out of round , or have badly worn tips , should also be replaced .



Yes , you may remove the head bolts that retain the rocker shafts . It will not disturb the gasket seal .