GM350 Cast Iron GM350 Complete Cylinder Head Assembly for Chevrolet Chevy SBC 350 5.7L 8 Valve – OEM 12558060

Product Overview: This complete cylinder head assembly is built for the GM 350 small-block Chevrolet V8 5.7-litre petrol engine, a cornerstone of American V8 passenger car and light truck production. It is supplied as a replacement assembly for a cracked, warped or valve-damaged original head and is machined to original equipment tolerances, making it suitable for repair, restoration and rebuild work.

Key Features: The casting is produced from high-strength cast iron and CNC-machined for accurate deck flatness, correct valve seat concentricity and consistent combustion chamber volume. Cylinder head machining follows factory dimensions for the intake and exhaust valve angles, and the unit is compatible with standard valve train components, intake manifolds and exhaust manifolds used on Chevrolet and GM applications. Manufacturing follows recognised quality management practices, and the head is inspected before dispatch.

Vehicle Compatibility: This head is designed for GM and Chevrolet 350 small-block V8 engines of 5.7 litres fitted to passenger cars, trucks and vans, with a stated direct replacement fitment. Because accessory mounting, emissions provisions and chamber specifications varied across production years, always verify the casting number and chamber volume against the original head before ordering.

Specifications: Engine code GM350; displacement 5.7 litres; V8 small-block; material cast iron; standard size; eight cylinders; new condition; direct replacement fitment; quality certified to recognised automotive standards; 12-month warranty; purpose replacement and repair.

OEM / Reference Numbers: 12558060 and 12529093. Match these references against the casting marks and part label on the original cylinder head to confirm the correct variant.

Applications: Suitable for passenger cars, pickups, vans, light trucks and performance or restoration projects powered by the Chevrolet 350, including general engine overhauls and rebuilds.

Benefits / Replacement Information: Replacing a failed head with this assembly restores compression, corrects coolant and combustion gas leakage, and resolves overheating caused by cracking or distortion. Cast iron construction provides durability and dimensional stability for high-load applications, and a complete assembly avoids the cost of reconditioning a badly worn casting.

Installation or Fitment Notes: Installation should be carried out by a qualified engine builder. Inspect the block deck for flatness, use the correct head gaskets and head bolts for the application, and torque in the manufacturer's specified sequence. Check valve train geometry, pushrod length and valve clearances during assembly, then run the engine and confirm there are no leaks before returning it to service.