Hyd Roller Lifter question

Hey guys so I purchased the Howard hydraulic roller lifter set for my 91' 360 from Summit. I'm also running the comp cams 280HR extreme energy cam. Upon installing my lifters, I realized that the stock skeleton frame/lifter retainer does not fit with the upgraded lifters. Is this a big deal? Do I need to have this installed to prevent unnecessary movement of the lifters? I'd like to get moving with the build at least to the point where the internals aren't exposed. the plans are for a 365ci with edie heads, rpm air gap intake, 750cfm demon, forged probe pistons, scat I beams, and stock crank. Everything is studded and ready for 450 horses.