Stage 1 Cylinder Head Package

Solid Performance Value

SKU: 165 Category:


This complete cylinder head package includes the best components available to enhance the performance of the 4G63 cylinder head. We will take your cylinder head and machine the seats to maximize airflow, install a set of high-flow nitride coated valves and high pressure beehive springs with titanium retainers. The component selection and machining processes have been carefully selected and perfected to work together providing you with an efficient cylinder head which offers power increases across the entire powerband. An emphasis is placed on low to mid lift flow enhancement. This is an excellent choice for use on stock shortblocks, bolt-on cars and applications seeing up to 20psi boost. This package includes stock-sized valves.

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
  • 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, standard size, nitride coated. 
  • Kiggly racing high pressure beehive springs with titanium retainers
  • Premium Viton valve seals


Additional information

Weight 48 lbs