Edelbrock Cyl Head Perf RPM AMC 290 304 343 360 390 401 V - 8 w Mach Exhst X - Over Complete

The Edelbrock 60139 Performer RPM cylinder head is designed as a bolt - on performance upgrade for any 1967 - 91 AMX, Javelin or Jeep with a 343, 360, 390 or 401 AMC V8 engine. They include adjustable rocker studs and guide plates set - up for use with small - block Ford style adjustable 1.61 ratio rockers. The intake flange is dual - drilled to accommodate early and late model intake bolt patterns, covering 1967 - 91. A Complete head includes larger than - stock valve springs to handle most high - lift cams. They feature stock location ports for compatibility with standard manifolds and headers. A direct bolt - on for 1970 and later engines with 12 head bolts, This head includes step - dowel pins for pre - 1970 engines. Their dual - quench combustion chambers produce approximately 9.51 compression in 401 V8 engines. The 45deg intake seat angle offers improved mid - to high - lift flow over the stock 30deg angle. The Edelbrock 601139 Performer RPM cylinder head has a machined heat crossover for 50 - state emissions legal performance.