Performer RPM Small-Bore Cylinder Heads are engineered for use with 265, 283, 305 and 307 c.i.d. small-block Chevy engines produced from 1954-2003 with 3.736" to 4.000" bores. Can also be used with larger bore engines if desired. Unlike our other Performer RPM cylinder heads, the valve spacing has been reduced to 1.817" to accommodate the smaller bores. These cylinder heads have the same great features as every Performer RPM series cylinder head, such as a thick deck, extra thick port walls, high-flowing ports, ductile iron seats, and high-quality rocker studs. The Performer RPM Small-Bore cylinder heads feature state-of-the-art compact combustion chambers and highly efficient ports that offer improved performance throughout the rpm range for great throttle response. They retain the stock straight spark plug angle and exhaust flange bolt pattern for ease of use with factory style exhaust systems. These cylinder heads utilize the early Gen 1 (1959-86) valve cover bolt pattern. Like all Edelbrock cylinder heads, these have been designed, tested and cast from A356 aluminum and heat treated to T-6 specs in Edelbrock's facilities in Southern California to guarantee you get the best from a name you can trust. ** Combustion chamber volume 60cc; Intake runner volume 170cc; Exhaust runner volume 62cc; Intake valve diameter 1.91 in.; Exhaust valve diameter 1.50 in.; V stem diameter 5/16 in.; V guides Maganese Bronze; Deck thickness 9/16 in.; V spring diameter 1.46 in.; V spring maximum lift 0.600 in.; Rocker stud 3/8 in.; Guideplate Hardened steel; Pushrod dia 5/16 in.; V angle 23°; Exhaust port location Stock; Spark plug fitment 14mm x .750 reach, gasket seat. ** INSTALLATION NOTE: Check cam manufacturer's specs for compatibility with v springs for spring rates. Match with Edelbrock intake gasket #7201, exhaust gasket #7204, valve cover gasket #7549 and head gasket #7310.
