Bolt-on Edelbrock performance for AMX, Javelin, Jeep and more. Designed for 1967-91 343, 360, 390 and 401 AMC engines. These heads include adjustable rocker stud and guide plate set-up for use with small block Chevy style adjustable 1.6:1 ratio rockers. The intake flange is dual-drilled to accommodate early and late model intake bolt patterns, covering 1967-91. Complete heads include larger-than-stock valve springs to handle most high-lift cams. Features stock location intake ports for compatibility with standard manifolds and headers. A direct bolt-on for 1970 and later engines with 1/2" head bolts, these heads include step-dowel pins for pre-1970 engines. Dual-quench combustion chamber produces approximately 9.5:1 compression in 401 V8s. 45 intake seat angle offers improved mid- to high-lift flow over the stock 30 angle. Performer heads #60129/#60139 have a machined heat crossover for 50-state emissions legal performance. Made in USA. Edelbrock AMC NHRA Performer RPM Cylinder Head - Bare 60107 NHRA Legal Cylinder Head Aluminum Bare 54cc Chamber 185cc Intake Runner AMC 343/360/390/401Pit Stop USAoffers Edelbrock AMC NHRA Performer RPM Cylinder Head - Bare 60107 at low everyday prices. Be sure to check out all of our products from Edelbrock including Edelbrock Aluminum Cylinder Heads - AMC.