Need help quick please oil problem with new motor

[302crew]

okay well i told all of you how i wasnt sure what was up with my car not having the proper oil pressure so i put in a new pump a high pressure one changed all the gaskets and when i was taking it apart there was metal peices in the bottom of my pan i got it all back toghetrer started it up and it had about 70 psi at an idle when it was cold as soon as it heated up it went to 19psi at an idle and about 40 to 50 when reving it to 6000 rpm could the bearings might have rusted when the motor was sitting for about a year and they are just worn out now and if so can i get away with just changing the bearings in the motor. cause it has only about 7000 miles on it also if i was to just takew out the bearings in the mains and rods and put new in would the motor still be balanced or would that have to be redone cause dss says the blocks are balanced and blueprinted some suggestions would help me so much right now if anyone would like to talk to me on AIM im smatt302 thanks for the hlep or advice in advance