Either get the lifters reconditioned, or install new ones. There are a few places that will regrind used lifters to their original contour. "Dragsix" has the name of a company he says can do that. I'm building a fixture for my lathe to re-contour lifter bases, but it's not in operation yet. I'd also strongly suggest contacting Schneider cams about getting that used cam reground so you're starting off with virtually new mating parts, then go through the traditional 20 minute fast idle break-in run like you would do with a new cam and lifters. If that cam has a steel core, not cast iron, you'll need to run chilled iron lifters to avoid rapid wear of both the cam and lifters. Good luck!
Jerry