Small Block Oiling System Mods

What happens in the case of rollers is the U shape cut for the roller itself, uncovers the cast in passage for the lifter bore galley. So there is a momentary low pressure "pulse" for each lifter, as it goes thru the motions. This effectively starves the lower end because the pass side lifter bores are fed first by the pump. The tubing mod gives the galley a liner, so it doesnt matter how far the lifter rises, the integrity of the gallery is maintained. It also stabilizes the flow to the lower end. Lifter bore bushings do the same correction for lifter, but also correct the lifter bore angles, which are never where they should be. Keep tabs on your oil pressure gage during warm up, and an eye on max pressure. I would put it on a dyno, do a little tuning, then pull the pan and check for any problems before putting it in the car.