Note: 1.65 ratio rocker arms with 3/8" adjusting nuts. Must machine cylinder heads and install 99156-16 3/8" rocker arm studs and aftermarket pushrod guideplates (special length heat treated pushrods required). Street/Strip Rocker Arms 80744-16$251.20 3/8" Rocker Arm Studs Set/16 See Product Info 99156-16$56.00