I'm rebuilding the L31out of my 96 GMC K2500 and am nearly to the point of putting the thing in. I know that it's best to prime the oil system before starting the truck, so I bought a proper tool that attaches to a drill. My engine has the oil filter housing that runs two lines to an oil cooler in the radiator, and when I spin the oil pump it comes right out of the holes for the lines on the oil filter housing. So my question is do I need to either somehow block the holes, or hook the lines up to both the rad and the filter housing and spin it then? Maybe possibly something entirely different I'm not thinking of but any help is greatly appreciated.