This roller lifter kit is used on all late models V8 blocks 1986 and newer. These second design lifters are used in late model 350 HO engines and use a higher checkball spring preload. This kit includes 16 of P/N 17120735 roller lifters, 8 of P/N 12550002 valve lifter guides, one of P/N 14101116 valve lifter guide retainers 4 of P/N 24501365 retainer bolts, and 4 of P/N 120386 retainer washers. This kit plus pushrod kit P/N 12371041 and a roller tappet design camshaft will convert your engine to a roller lifters engine. Use kit items listed above for single service parts.