Product Description
Mangum Racing CNC Ported 267cc LS3 Cylinder Heads
Deck Milling Available (email Sales@michiganmotorsports.com prior to ordering)
Built from their own 6-bolt 15° LS3 casting featuring increased deck thickness, the Mangum Racing 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 a 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.
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 available ($50)
- 1/2" head stud hole upgrade available ($50)
- Flat milling at .006” per cc available
- Minimum bore: 4.000”
- Sold/Priced as a Pair
For builders who need to retain OEM valve angles and locations but demand serious airflow capability, the MR 15° LS3 casting delivers.
