I past I have purchased some of these “NOS” sealed wrapped oil pumps. However they offer very different oil pressures (on the same engine). It looks these are not NOS but rebuilt and repackaged in past???
Most important question: what part or section is usually damaged? Where is the oil pressure loosing? I have also these NOS rebuild kits, want try change some parts…?

Is that a solution or the body is a problem???
Thanks