I bought a 'Jasper' remanufactured 350 in my 1990 Silverado. It was really the best money I've spent. Now 09 years later the engine runs so smooth you can put a cup of coffee on the dash and there's not a ripple in the coffee. Now whenever I'm in the truck it stays at 60 pounds at cold idling, and when it's warmed up I have 30 PSI at Idle and when up at speed like 50 or 60 Mph it stays at 45 PSI. One thing Jasper does when they do the rebuild is to install a high volume oil pump and a 3 year or 100.000 mile warranty. It is perfect product. But in your case I'd drop the pan and put in a new high volume oil pump. I have a standard oil pump in my 88 K5 Blazer with a 350 in it. Even as standard 30 year old engine configuration I get 45 PSI at cold and when warmed up I still have 30 PSI a little lower with the A/C maxed out at 28 PSI oil pressure. Hope this helps you out. Good luck !