C6 Corvette Heads

Mangum Racing 273cc Qualcast LS7 Cylinder Heads

Mangum Racing CNC Ported 273 LS7 Cylinder Heads

Built from the Qualcast stock style replacement LS7 casting, the Mangum Racing 273 program is designed for high-rpm, large-displacement LS combinations that demand elite airflow and structural integrity.

Featuring a 12° valve angle and OEM LS7 valve spacing/valve length, this 6-bolt casting delivers exceptional port efficiency while maintaining compatibility with LS7-based platforms. With a 273cc CNC intake runner and optimized 93cc exhaust port, this cylinder head is engineered for serious naturally aspirated builds and high-output boosted applications where the customer wants a near bolt on cylinder head.

Each set is fully CNC machined in-house on our Centroid 5-axis machining centers and finished on Newen seat and guide equipment. Every head is hand blended, assembled, and inspected in small batches to ensure dimensional accuracy and repeatable performance.

Airflow Performance

Tested on a SuperFlow 1020 with a 4.125” bore plate

Intake (Radius Entry)

• .200” – 160 CFM
• .300” – 255 CFM
• .400” – 311 CFM
• .500” – 352 CFM
• .600” – 380 CFM
• .700” – 390 CFM

Exhaust (No Pipe)

• .200” – 117 CFM
• .300” – 160 CFM
• .400” – 209 CFM
• .500” – 221 CFM
• .600” – 230 CFM
• .700” – 244 CFM

The 273 LS7 delivers outstanding mid-lift efficiency with dominant high-lift airflow, making it ideal for aggressive street / strip combinations.

Premium Hardware & Construction

• 6-bolt Qualcast LS7 casting
• 12° valve angle with OEM LS7 valve spacing
• Stock Valve Lengths
• 273cc CNC intake port
• 93cc exhaust port
• 70.5cc CNC combustion chambers (milling available at no charge)
• 2.200” titanium intake valves
• 1.610” stainless exhaust valves
• Bronze CHE guides
• PAC .660” dual spring package
• Titanium retainers
• Viton seals
• 1.250” steel spring seats
• Chamber softening available
• Flat milling at .006” per cc
• Minimum bore: 4.100”

Designed for LS7 Street & Strip Builds

With airflow over 390 CFM at .700” lift, the Mangum Racing 273 LS7 is capable of supporting serious naturally aspirated horsepower in 427+ cubic inch combinations.

Stock pushrod length works in many applications but should always be verified based on camshaft selection and final milling.

Precision Race Components LS7 CNC 265cc ported cylinder heads.

• Based off PRC's CNC Ported LS7 Heads
• 2.200"/1.610" Valves (base price for exchange includes new stainless exhaust valves)
• Available with PRC Double Spring Kit Complete With PRC Double Springs, Titanium Retainers, Seats, & Seals
• Completely Assembled & Setup To Your Specs!!
• Available With Stainless, Hollow Stems, or titanium valves!

• 2.165"/1.59" Valves
• PRC Double Spring Kit AVAILABLE
• Completely Assembled & Setup To Your Specs!!

• Cylinder Head Cleaning
• CNC Valve Job
• CNC Porting
• Milling to customers specs
• Fully Assembled

*Typically a 1-2 week turn around time once heads arrive at our facility.

All Precision Race Components (PRC) cylinder heads come fully CNC-ported and machined using state-of-the-art technology!

Click Here to SEE why we build better heads!

MADE IN THE USA!!

CAST IN THE USA!!

MACHINED IN THE USA!!

PRC's aftermarket casting LS3/L92/L99 cylinder heads come standard with the following options:

• NEW PRC 13-Degree Valve Angle LS3 Castings
• Improved Piston-to-Valve Clearance For Extra Compression & Larger Camshafts
• Smaller Than Stock Intake Port Volume For Improved Port Velocity
• Manley Stainless 2.185" Intake, 1.60" Exhaust Valves
• Billet Rocker Pedestals
• TSP .660" Dual Spring Kit w/ PAC Valve Springs, Titanium Retainers, Seats, & Seals
• CHE Bronze Guides
• Completely Assembled and Milled to Your Specifications
• 60-68cc Chambers

All PRC cylinder heads are extensively researched and tested. The all-new PRC aftermarket casting LS3 cylinder heads are designed to flow considerably more than a gm ported casting while keeping the port sizes smaller for improved port velocity. The result is a cylinder head that is smaller than a stock GM LS3 port and moves more air than any other ls3 cylinder heads! 

The all new PRC aftermarket casting LS3 heads are the perfect option for customers looking for the ultimate in LS3/L99/L92 cylinder head technology

The PRC aftermarket casting LS3 cylinder heads are available in 2 different configurations: 

• 255cc Runners for max effort stock cube LS2/LS3/L99/L92 engines looking for a 370cfm cylinder head that can be aggressively milled & still keep better than stock p/v
• 260cc Runners For LS3/L99/L92 stroker engines needing a 380cfm+ cylinder head!

The 13-degree valve angle will allow for the ability to run more compression and larger camshafts thanks to additional piston-to-valve clearance!!  

With all PRC cylinder heads, quality and performance are our two highest priorities! In addition to performance, you will not find a better performing set of cylinder heads at this price (cost is for the pair!). Call one of our sales consultants today if you have any questions or if you would like to discuss your specific application. 

Precision Race Components all new cylinder head castings completed with 247cc runners. For 408 cubic inch and larger applications with 4.03"+ bore sizing.

Click Here to SEE why we build better heads!

• 247cc Fully CNC Ported Intake Runners
• 84cc Fully CNC Ported Exhaust Runners
• TSP Dual Spring Kit w/ PAC Springs Rated To .660" Lift
• 68cc CNC Machined Chambers
• CHE Bronze Guides
• 2.120" Intake / 1.600" Stainless Valves
• Factory Rocker Friendly!!*
• ***NOW AVAILABLE WITH HOLLOW STEM INTAKE VALVES!!! SAVES APPROXIMATELY 15 Grams!!!***