PRC 225cc As-Cast Cathedral-Port Cylinder Heads — LS1/LS2 Applications

PRC 225cc As-Cast Cathedral-Port Cylinder Heads — LS1/LS2 Applications

Part Number: PRC-SSAsCast225

Precision Race Components PRC-SSAsCast225 cylinder heads combine high-flow 225cc as-cast cathedral-port intake runners with CNC-machined combustion chambers and valve-guide machining for high-performance LS applications. PRC designed the 225cc casting to support combinations ranging from performance street engines with moderate camshafts through substantially higher-output naturally aspirated and boosted builds.

The current 62cc version uses a compact CNC-machined chamber to increase compression and improve power potential in appropriately matched combinations. PRC reports more than 320 CFM of intake airflow, while retaining compatibility with factory LS1-style rocker arms and supplying the heads with TSP/PAC dual valve springs and titanium retainers.

Key Features

• 225cc as-cast cathedral-port intake runners
• CNC-machined 62cc combustion chambers
• CNC-machined valve-guide areas
• PRC flow-bench tested intake airflow of more than 320 CFM
• 2.065-inch 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
• Cast and machined in the USA

Kit Includes

• Pair of fully assembled PRC 225cc as-cast cathedral-port cylinder heads
• 2.065-inch 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: 62cc
• Combustion chamber finish: CNC machined
• Intake valve diameter: 2.065 in
• Exhaust valve diameter: 1.600 in
• 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 cathedral-port LS applications and marketed by PRC/Texas Speed for LS1/LS2 combinations.
• Texas Speed currently recommends the 225cc head family primarily for 5.7L, 6.0L, and larger cathedral-port LS combinations.
• The current 225cc head/cam package documentation specifies a minimum 3.903-inch cylinder bore for clearance with the 2.065-inch intake valve. Verify bore diameter and valve-to-cylinder clearance for the specific short block before final assembly.
• The 62cc chamber is intended to increase compression relative to larger-chamber combinations. Final compression ratio depends on displacement, piston configuration, deck height, head-gasket dimensions, and chamber volume.
• PRC also offers a separate 68cc big-chamber version under a different part number. PRC-SSAsCast225 is the 62cc configuration and should be cataloged separately rather than as a chamber-size variant.
• 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.