Dart 19474136 Pro 1 CNC Aluminum BB Chevy Cylinder Heads Assembled (1 head)

Dart Pro 1 CNC Ported Big Block Heads are professional quality competition cylinder heads. Dart applied the airflow technology developed in their championship winning Pro Stock engine program to produce these state of the art heads. Every intake port, exhaust runner, valve bowl, and combustion chamber is 100% CNC machined on special dedicated Pro 1 castings. Their five-axis, computer controlled machining centers produce compound curves and complex shapes that no human could duplicate with a hand grinder. Dart Pro 1 CNC Ported Big Block Heads feature premium alloy cast from virgin 355-T61 aerospace alloy for superior strength and integrity, bolt on compatibility, 2 degree rolled valve angle and standard spacing accommodating all stock accessories, 335cc and 355cc intake ports so you can match the runner volume to your engine's displacement and rmp range, heart shaped 121cc chambers improve combustion efficiency, CNC machining ensures that every chamber has the same volume so every cylinder has equal compression efficiency, CNC machining ensures that every chamber has the same volume so every cylinder has equal compression, raised spark plug location improves flame travel for a quicker, more complete burn, producing more power, multi-angle intake seats and radiused exhaust seats dramatically increase airflow, hardened exhaust seats are compatible with unleaded gasoline, exhaust ports raised .300" to improve flow (requires 1" longer head bolts next to exhaust ports), spark plug holes are machined for gasketed 3/4" reach plugs, manganese bronze valve guides extend cylinder head life and reduce stem wear.