Designed for 1986-and-later engines. Second-design lifters are used in late-model 350 HO engines and use a higher checkball spring preload. Includes 16 lifters of P/N 17120735, eight valve lifter guides, one valve lifter guide retainer, four retainer bolts, and four retainer washers. This lifter kit plus pushrod kit P/N 12371041 and a roller-tappet design camshaft converts your engine to a roller-lifter engine. For single lifter usage, use P/N 17120735. This kit includes the following items: 17120735 16 Roller Lifters 12550002 8 Lifter Guides 14101116 1 Guide Retainer"