These are direct fit original style replacements for the cast-iron manifolds used on 1963-1967 289 High Performance, or K-code, engines. 289 HiPo manifolds were engineered by the factory to provide more flow than the standard passenger car manifolds offered. These authentic reproductions feature the correct markings and raised part numbers for early 289 HiPo cars. These manifolds are a durable, original style upgrade compatible with non HiPo 260, 289 or 302 small block engines. Sold as a pair, four studs and nuts are included. Installation on non hi-po cars will require the use of a 289 HiPo or a custom H-pipe, manual transmission cars may require the use of a 289 HiPo clutch linkage.