PRC 225cc As-Cast Cathedral-Port Cylinder Heads — 68cc Big Chamber

PRC 225cc As-Cast Cathedral-Port Cylinder Heads — 68cc Big Chamber

Part Number: PRC-SSAsCast225BC

Precision Race Components PRC-SSAsCast225BC cylinder heads combine high-flow 225cc as-cast cathedral-port intake runners with CNC-machined 68cc combustion chambers and valve-guide machining for high-performance LS1/LS2 applications. The larger 68cc chamber is intended for combinations where additional chamber volume is desirable, including larger-bore, stroker, and boosted LS builds.

PRC reports more than 320 CFM of intake airflow from the 225cc as-cast intake port. The heads use 2.065-inch stainless-steel intake valves, 1.600-inch stainless-steel exhaust valves, factory LS1-style rocker arms, and are supplied assembled with TSP .660-inch dual valve springs using PAC springs and titanium retainers.

Key Features

• 225cc as-cast cathedral-port intake runners
• 68cc CNC-machined combustion chambers
• CNC-machined valve-guide areas
• PRC flow-bench tested intake airflow of more than 320 CFM
• 2.065-inch stainless-steel intake valves
• 1.600-inch stainless-steel exhaust valves
• TSP .660-inch dual valve-spring package with PAC springs
• Titanium valve-spring retainers
• Uses factory LS1-style rocker arms
• Designed for large-bore, stroker, and boosted cathedral-port LS combinations
• Cast and machined in the USA

Kit Includes

• Pair of fully assembled PRC 225cc as-cast cathedral-port cylinder heads
• 2.065-inch stainless-steel intake valves
• 1.600-inch stainless-steel exhaust valves
• TSP .660-inch dual valve springs with PAC springs
• Titanium retainers

Technical Specifications

• Intake port configuration: Cathedral port
• Intake runner volume: 225cc
• Combustion chamber volume: 68cc
• Combustion chamber finish: CNC machined
• Intake valve diameter: 2.065 in
• Exhaust valve diameter: 1.600 in
• Valve material: Stainless steel
• Valve-spring configuration: TSP .660-inch dual spring kit with PAC springs
• Retainers: Titanium
• Rocker-arm compatibility: Factory LS1-style rocker arms
• Published peak intake flow: 321 CFM @ .650-inch lift
• Published peak exhaust flow: 230 CFM @ .650-inch lift

Published Flow Data

Application Notes

• Designed for LS1/LS2-style cathedral-port LS applications requiring a high-flow aftermarket cylinder head.
• The 68cc chamber provides additional chamber volume compared with the 62cc PRC-SSAsCast225 version and is intended for applications where lower static compression or additional combustion-chamber volume is desirable.
• PRC specifically positions this version for larger-bore combinations such as stroker and boosted applications.
• Final compression ratio depends on displacement, piston configuration, deck height, head-gasket dimensions, and actual chamber volume.
• Pushrod length, piston-to-valve clearance, and valvetrain geometry should be verified for the complete engine combination.
• Head gaskets, head bolts or studs, rocker arms, pushrods, intake manifold, exhaust components, and installation gaskets/hardware are not listed as included with this cylinder-head set.

Emissions and Competition-Use Notice

This product is not legal for sale or use in the state of California. Installation or use on an emissions-controlled vehicle may also be restricted by federal, state, or local law. The purchaser and installer are responsible for confirming that the completed vehicle and application comply with all applicable emissions and vehicle-use requirements.