Quite a few old Volvos and Porsche race motors resurface their hard to replace mushroom lifters. The Fiat performance shop locally quoted Mopar dumbell solids for $3 a piece as it takes about 30 seconds to do one. They have to use the proper radius grinder stone on a dedicated lifter grinder or a Sioux or B&D valve grinder attachment. Not sure how thick the bottom of a Hi-Energy lifter is to get reground, probably thick enough.