GMC engines are full pressure from the factory with rifle drilled cranks. The Tech Tip is for providing full filtration - diverting all oil flow through the filter. Back in the day there were no detergents in oil. This caused contaminants to fall into the pan - which could be scrapped during periodic service intervals. Those engines that had oil filters were only by-pass affairs where some oil passed through the filter via peripheral circuit. Once the filter became clogged no oil passed through the filter. When converting to full flow through the filter circuit the remote filter housing needs incorporate a bypass or you could the starve the main oil gallery.
