Clearance Parts - Mail Order Tuner

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

IN STOCK 

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 267cc LS3 Cylinder Heads

Mangum Racing CNC Ported MR 15° LS3 Cylinder Heads

Built from our 6-bolt 15° LS3 casting featuring increased deck thickness, the MR 15° LS3 is engineered for serious naturally aspirated and boosted combinations that demand airflow, strength, and repeatability — while maintaining OEM valve angle and valve location geometry.

This casting is designed to support 1,500+ horsepower combinations when paired with the proper short block and induction system, making it an ideal solution for builders who need maximum performance without moving away from stock valve layout.

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

Airflow Performance

Tested on a SuperFlow bench with a 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, the MR 15° delivers strong mid-lift efficiency and stable high-lift airflow — ideal for aggressive hydraulic roller and race-oriented camshaft profiles while retaining factory valve geometry.

Premium Hardware & Construction

• 6-bolt Mangum Racing LS3 casting with increased deck thickness
• 15° valve angle with 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
• Flat milling at .006” per cc
• Minimum bore: 4.000”

Built for High-Output Stock-Geometry Combinations

The increased deck thickness provides added durability under elevated cylinder pressure, while the 15° valve angle maintains compatibility with stock-style piston valve reliefs and factory-based valvetrain geometry.

The PAC .660” dual spring system offers the stability required for serious street or race camshaft profiles, and stock pushrod length works in many applications (final length should always be verified based on camshaft and milling).

For builders who need to retain OEM valve angles and locations but demand serious airflow capability, the MR 15° LS3 casting delivers.

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!

Mangum Racing 275cc 11° LS3 Cylinder Heads

Mangum Racing CNC Ported MR275 11° LS3 Cylinder Heads

Built from the Mangum Racing 6-bolt 11° LS3 casting featuring a massive .750” deck surface, the MR275 is designed for maximum-effort naturally aspirated and boosted LS combinations where airflow, strength, and valvetrain stability are non-negotiable.

This casting was engineered for builders who want every available advantage — valve angle, deck thickness, port efficiency, and piston-to-valve clearance — all optimized to support serious compression and high cylinder pressure environments.

Each set is fully CNC machined in-house on brand new Centroid 5-axis machining centers and finished on Newen seat & guide equipment. Every head is hand blended, inspected, and assembled in small batches to ensure repeatability and precision.

Airflow Performance

Tested on a SuperFlow bench with a 4.125” bore plate

Intake (Radius Entry)

• .200” – 143 CFM
• .300” – 221 CFM
• .400” – 283 CFM
• .500” – 330 CFM
• .600” – 358 CFM
• .700” – 381 CFM

Exhaust (No Pipe)

• .200” – 112 CFM
• .300” – 161 CFM
• .400” – 202 CFM
• .500” – 232 CFM
• .600” – 242 CFM
• .700” – 248 CFM

With a 275cc CNC intake runner and optimized 98cc exhaust port, the MR275 delivers exceptional mid-lift efficiency with dominant high-lift airflow. The 11° valve angle significantly improves piston-to-valve clearance, allowing aggressive cam timing and higher compression strategies without compromise.

Premium Hardware & Construction

• 6-bolt Mangum Racing 11° LS3 casting with .750” deck thickness
• Optimized 11° valve angle and revised valve locations
• 2.185” hollow stem stainless extended-length intake valves
• 1.600” stainless extended-length exhaust valves
• Bronze guides
• Choice of PAC 1207X, 1208X, or 1209X dual spring packages
• Titanium retainers
• Viton seals
• 1.250” steel spring seats
• 70.5cc fully CNC chambers (milling available at no charge)
• Chamber softening options for 4.000”, 4.065”, and 4.125” bore sizes
• Flat milling at .006” per cc
• Substantial piston-to-valve clearance for advanced camshaft profiles and compression increases
• Minimum bore: 4.000”

Built for Maximum Effort Combinations

The increased deck thickness supports extreme cylinder pressure in large displacement and boosted applications. The revised 11° valve angle enhances airflow efficiency while providing additional mechanical clearance — a critical advantage in high-rpm, high-lift camshaft programs, or builds where smaller combustion chambers are required.

These heads have supported combinations exceeding 2,000 horsepower and 200+ mph in competition environments, making the MR275 a proven solution for serious LS3-based builds.

If you are building a no-compromise LS3 combination — naturally aspirated or power-adder — the MR275 was designed for exactly that purpose.

• 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)

BTR Gen 3 and Gen 4 LS Truck Norris Camshaft 

212/22X .552/.552 107 LSA 

• The Truck Norris will deliver a roundhouse kick in the pants to your 1999-2013 GM V8 Truck or SUV! Developed from hundreds of hours of in-house cam lobe design and dyno testing, this camshaft has more power and torque everywhere in the curve compared to BTR's legendary V2 truck cams. It has an idle sound similar to more aggressive truck camshafts, yet will behave well with stock torque converters.

IN STOCK 

Chevrolet Performance LS7 lifter set is an OE hydraulic roller lifter that can be used in all non-DOD LS and Gen 5 LT engines.

LS7 Lifters – (FAQ’s) Frequently Asked Questions