There are numerous types of lifters both solid and solid roller out there that one wants to research before installing as the oil holes are sometimes different from one to the other. The older rollers had the smaller oil holes, the newer ones have gargantuan holes in them that will flow enough oil to float a battleship!!I found this out the hard way by losing the bottom end to filling up the top end with oil. With bushings installed, it controls the oil flow to the top regardless of which lifter you use; even the Windsor lifters will work. With bushings a .040 to .060 hole will provide sufficient flow of oil to the top to keep it alive and well.