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.
