Page 159 of GM Performance Parts 2006 Catalog by GM Parts Direct

157 NOTE: NOTE: NOTE: ROCKER ARMS A. 12495490 Rocker Arm Kit, 1.5 ratio (set of 16) These self-aligning, high-quality rockers have a nominal 1.5:1 ratio. Kit includes 16 stamped steel rockers with pivot balls and nuts. Use P/N 10089648 for single service part. For 3/8" studs. Does not fit LS Series engines. Not recommended for mechanical lifter camshafts. ALUMINUM ROLLER ROCKER ARM 3/8" STUDS These roller rocker arms are similar to the rockers used in the 1996 Corvette LT4 engine, except the trunnions have been machined for early-model 3/8" rocker studs. These arms offer about 2 lb.-ft. in rotation torque for a quieter idle.The arms are self-aligning with improved stiffness and accommodate up to 0.575" valve lift. Choose from 1.5:1 and 1.6:1 ratios below. 12370838 Roller Rocker Arm Set, 1.5:1 ratio (not shown) Set of 16, 3/8" stud 1.5:1 ratio roller rockers. Use P/N 12367345 for single service part. 12370839 Roller Rocker Arm Set, 1.6:1 ratio (not shown) Set of 16, 3/8" stud 1.6:1 ratio roller rockers. Use P/N 12367346 for single service part. When using a high lift camshaft, check valve spring coil bind, retainer-to-seal clearance, and piston-to-valve clearance. Check for adequate pushrod clearance when using on cast iron heads. It may be necessary to remove valve cover drippers for proper rocker arm clearance. P/N 12370839 cannot be used on ZZ3 engines with orange valve springs. 12367347 Adjuster Nut for Roller Rocker Arm (not shown) This 3/8" adjustment nut is used on both aluminum rocker arm kits P/N 12370838 and P/N 12370839. 88961233 "Kool Nut" Rocker Arm Kit (not shown) Special rocker arm nuts, known as "kool nuts," are used on GM circle track engines. Package contains 16 pieces. ALUMINUM ROLLER ROCKER ARM 7/16" STUDS These roller rocker arms are for 7/16" studs and are CNCmachined from aluminum alloy. The bearings and fulcrum have an extra-wide design for load distribution and are lubricated with pressurized oil. The roller tip axle is made from 4130 steel, and the roller tip is machined and ground from 8620 steel. Bowtie logo is machined into each rocker. Choose from 1.5:1 and 1.6:1 ratios below. B. 12361321 Roller Rocker Arm Set, 1.5:1 ratio Set of 16, 7/16" stud 1.5:1 roller rocker arms. Use P/N 12361328 for single service part. 12361322 Roller Rocker Arm Set, 1.6:1 ratio (not shown) Set of 16, 7/16" stud 1.6:1 roller rocker arms. Use P/N 12361329 for single service part. These aluminum rockers will not work with standard-height valve covers. When using a high lift camshaft, check valve spring coil bind, retainer-to-seal clearance, and piston-to-valve clearance. Check for adequate pushrod clearance when using on cast iron heads. It may be necessary to remove valve cover drippers for proper rocker arm clearance. Rocker Arm Kit, 1.5 ratio (set of 16) A Roller Rocker Arm Set B Standard Roller Rocker Arm B Standard Roller Rocker Arm B

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