Mangum Racing 267cc LS3 Cylinder Head

IN STOCK 

This kit includes everything needed to delete AFM/DOD (Active Fuel Management) from GM L83, LT1/L86 Dod Delete Kit w/ Camshaft.

TUNING REQUIRED

This Kit Includes The Following:

• DOD Hole Plug
• 2014+ LT1 Head Bolt Kit
• GM/Delphi LS7 Style Lifter, Set of 16
  
• TSP OE Style Gen 5 5.3 Head Gasket (Each)
• 2014+ LT1 Stingray Valley Cover Gasket
• GM LS1/LS6/LT1 Wet Sump Balancer Bolt
• LT1 Stingray Exhaust Manifold Gasket Each
• GM LT1 & 2014-2018 L83/L86 Cam Phaser Bolt / Valve
  
• TSP OEM-Style Non-DOD Camshaft
• TSP LS/LT Front Crank Seal 
• GM LS3 Lifter Trays - Set of 4
• Water Pump Gasket 2014+ LT1

• 2019+ DOD Hole Plugs
• 2014+ LT1 Head Bolt Kit
• GM/Delphi LS7 Style Lifters (Set of 16)
• TSP OE Style Gen 5 5.3 Head Gasket (Each)
• 2014+ LT1 Stingray Valley Cover Gasket
• GM LS1/LS6/LT1 Wet Sump Balancer Bolt
• LT1 Stingray Exhaust Manifold Gasket (Each)
• GM LT 2019+ Cam Phaser Bolt / Valve
• TSP OEM-Style Non-DOD Camshaft
• TSP LS/LT Front Crank Seal
• GM LS3 Lifter Trays (Set of 4)
• Water Pump Gasket (2014+ LT1)

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.

Mangum Racing Brodix 267cc LS3 Cylinder Heads

Mangum Racing CNC Ported Brodix 15° LS3 Cylinder Heads

Built from Brodix 6-bolt LS3 castings with extra deck thickness, our Mangum Racing 15° LS3 heads are designed for serious naturally aspirated and boosted combinations that demand airflow, strength, and repeatability.

Each set is fully CNC ported in-house with brand new Centroid 5-axis CNC mills and Newen seat & guide machines. Every set of cylinder heads is hand blended and carefully inspected before final assembly to ensure dimensional accuracy and consistency.

Airflow Performance

(4.125” Bore Plate)

Intake (Radius Entry)

• .200” – 148 CFM
• .300” – 227 CFM
• .400” – 282 CFM
• .500” – 325 CFM
• .600” – 350 CFM
• .700” – 363 CFM

Exhaust (No Pipe)

• .200” – 114 CFM
• .300” – 164 CFM
• .400” – 200 CFM
• .500” – 233 CFM
• .600” – 240 CFM
• .700” – 243 CFM

With a 267cc CNC intake runner and optimized 96cc exhaust port, these heads deliver strong mid-lift numbers with excellent high-lift stability — making them ideal for aggressive hydraulic roller street & race builds needing to retain the stock valve locations & angles.

Premium Hardware & Construction

• 6-bolt Brodix LS3 casting with increased deck thickness
• 15° valve angle, OEM LS3 valve spacing
• 2.165” hollow stem stainless intake valves
• 1.600” hollow stem stainless exhaust valves
• Bronze guides
• PAC .660” dual spring package
• Titanium retainers
• Viton seals
• 1.250” steel spring seats
• 68.5cc CNC chambers (milling available at no charge)
• Chamber softening options for 4.000”, 4.065”, and 4.125” bore sizes
• .006” per cc flat milling available
• Minimum bore: 4.000”

Designed for Builders Who Care About the Details

These are not mass-produced heads. Each set is machined, assembled, hand blended, and inspected in small batches to maintain strict quality control and dimensional consistency.

Extra deck thickness adds durability for higher cylinder pressure combinations. The PAC .660” dual spring setup provides valvetrain stability for serious cam profiles. Stock pushrod length works in most applications but should always be verified based on camshaft and final milling.

If you’re building a combination needing to stay stock valve angles & locations then this cylinder head is hard to beat!