i have a dakota with a 1970 318 in it. I have a manual guage setup, the oil pressure guage reads about 50-60 psi on cold startup but within minutes drops to 7-9 idling and going down road only runs 15-20psi.. could pcv valve and breather on valve cover unhooked cause this???

 

That sounds about right for a high mileage engine. Did you rebuild the motor?

 

mine does the exact same thing, its normal...

 

the guy i bought it from said he checked everthing when he had it apart and it was good.I recently replaced the oil pump,pickup tube, and filter and had no effect, I am running a fram oil filter and some people are saying that the filters are no good and could be a problem. have you heard of this????

 

I used to run a fram oil filter on my truck and my oil pressure was always low. I changed up and started using a WIX oil filter, and it helped out alot. My pressure stays good on my guage now. Im not saying that it will help your truck but it did mine. I run WIX oil and air filters on my truck now.

 

i also heard the fram filters can come apart and clog up the motor too.
what guage do you have for your oil pressure(mechanical right?). i put a mechanical gauge in my truck after i blew the factor electrical one off the motor and it does the same thing as yours. it is normal for it to move like that. if you want to be sure its not low or something then you could hook the factory one up and try it for a bit to see the difference.

 

it is a mechanical gauge, have brandnew gauges,and today bought a new super tech filter #st16. I know it's not the best but it will do for now. hopefully I will get some effect. If anybody need a crossreferance ;
Fram Extraguard PH43
STP S8A
SuperTech ST16

 

when mine did that i used motor flush ran 3 quarts of clean oil through it after emptying it then put a k and n oil filter and mobil 1 synthetic and boom it was fine so next change used the cheep stuff and it works fine.