Have a Magnum 360 in my 37 Plymouth and the oil pressure has been slowly dropping over the past year or so. So, I have purchased a new high volume pump as a precaution.

My question is, I know you need to prime a new pump on a newly built engine to make sure the bearings etc are oiled properly before starting. Do you need to prime the pump on a currently running engine? Would it be best to crank it a few times to build pressure with the coil wire off so that it doesn't start? Seems like something I should know, but don't.