my poor f250 maybe any suggestions

i have a 85 ford f250(351w)...it looses oil pressure after maybe about 12 miles and starts knocking at about 55....35 or 50 it doesnt knock and sounds fine....im thinking maybe oil pump but not sure...my question is if there is anything out there ,such as top of the line oil treatment or lubricant that i may try before i put alot of money into it..any suggestions would be greatly appreciated...thank you very much.......

Please see the responses in your identical posting at: http://www.automotiveforums.com/vbulletin/showthread.php?t=947632

Please see the responses in your identical posting at: http://www.automotiveforums.com/vbulletin/showthread.php?t=947632
im talking about the best lubricant treatment for it..im not much of a big mechanic and just trying to get by the cheap way...

im talking about the best lubricant treatment for it..im not much of a big mechanic and just trying to get by the cheap way...

First I would change the oil and use a straight 40 weight oil(50 weight oil if you can find it) NAPA sells a 40 weight oil, made by Valvoline I understand. Obviously also change the filter, I prefer Motorcraft. Substitute 1 or 2 quarts of the oil with Lucas oil stabilizer. I think you would be wasting your time and money changing the oil pump, the knocking you are getting is very likely worn connecting rod, or possibily main, bearings. A bearing may fail completely at any time, but the thicker oil may give you more time. PS: I would never use Lucas oil stabilizer in a good engine, it's juat an oil thickener. The only real cure for your engine would be to remove the engine, have the crankshaft turned and use undersize bearings, of course also new pistons and rings etc. Good luck with it, whatever you decide.