Stage 3 Cylinder Head Package

Solid Performance Value

SKU: 165 Category:


The JAM Stage 3 cylinder head package is designed for use on larger displacement engines with higher boost or smaller displacement race engines utilizing high RPM. This cylinder head includes +1mm oversized valves, full porting including combustion chamber enhancement, manganese bronze valve guides and dual valve springs. Please call or email us to discuss the particular aspects of your project. Since the heads are custom ported for each customer, we have the ability to tailor the head to your needs to maximize its efficiency.

Available for 6 and 7 bolt DSM and Evo 4-9. Good core is required.

The following procedures are performed to your cylinder head:

  • Complete disassembly and cleaning
  • Visual inspection and evaluation
  • Pressure test to reveal any cracks in the casting
  • Remove stock guides
  • Perform stage 2 port work which includes port match, blend the bowls and smooth casting flash and imperfections, fully port intake runners and smooth the combustion chambers.
  • Install a set of high performance manganese bronze guides and hone to size
  • Machine seats to larger ID to fit +1mm valves
  • Valve seats are machined in-house to enhance airflow
  • Valves are machined and back-cut to compliment the seats and enhance airflow
  • Valves are hand-lapped to the seats to maximize sealing
  • Valve heights are set to within +/-.001″
  • Valve spring pressures are checked and set to our specifiations based on your application
  • The deck surface is resurfaced to RA40 (suitable for use with MLS gaskets)
  • All components are final washed and the head is assembled with new Viton premium valve seals

The following parts are included:

  • JAM custom valves, +1mm oversize, nitride coated.
  • Manganese bronze valve guide set
  • Manley dual ¬†springs with titanium retainers
  • Hardened valve locks
  • Premium Viton valve seals


Additional information

Weight 48 lbs