JAK'S Performance Cylinder Heads
Four proven stages of horsepower and durability for the platforms that work the hardest. Every head is built with premium components, inspected by JAK'S Diesel, and backed by our own warranty.
Stage 3 · CAT C15 ACERT · CNC ported & loaded
Cast Right, From The First Pour
Every JAK'S head starts as a brand-new casting — no reman cores, no welded repairs. Here's how the casting is made and proven before it's machined, assembled and inspected.
Materials
High-grade low-carbon steel and raw iron are melted in an electric furnace and spectrometer-tested before every pour — keeping the chemistry consistent from one casting to the next.
Core Making
A fully automatic line forms, immerses and dries each sand core under robot handling. Only tested, qualified cores move on to the automatic pouring line for continuous, stable production.
Heat Treat & Test
Each cast blank is desanded, polished and heat-treated to relieve residual stress, then checked for appearance, inner cavity, hardness and tensile strength before any machining begins.
Machined, Cleaned, Assembled & Shipped
Once the casting passes inspection, every head is precision-machined, assembled and protected for transit — then inspected by JAK'S Diesel before it ships to you.
Precision CNC Machining
Advanced CNC equipment cuts every critical surface to exacting tolerances, so each head is precise and consistent across the entire run.
Thorough Cleaning
Every part is cleaned inside and out with high-pressure, high-flow systems to remove all contaminants and ensure peak performance.
Precision Assembly
Every component is assembled with precision tooling and tightly controlled processes for accuracy, reliability and long-lasting performance.
Secure Packaging
Packaging is built to protect every head in transit, so it arrives in perfect condition — ready for the job.
Four Stages, One Standard
From a clean OEM-spec replacement to a full competition build — same standard, same testing, same warranty. Pricing shown with core exchange.
Stage 1
Stage 2
Stage 3
Stage Comparison
Exactly what changes as you move up. Every stage ships loaded, lash-set, flow-verified and warranty-backed.
| CAT C-15 pricing | Stage 1 Daily Driver $2,999.99 Shop |
Stage 2 Upgraded $3,399.99 Shop |
Stage 3 Performance $3,699.99 Shop |
Stage 6 Max Output $5,199.99 Shop |
|---|---|---|---|---|
| Best for | Stock fleet rebuilds | High-mileage haulers | Tuned work trucks | Max-power builds |
| Valve job | OEM 3-angle | Performance | Performance | Full competition |
| Valve material | Standard valves | Inconel intake or exhaust | Inconel intake & exhaust | Coated Inconel intake & exhaust |
| Valve size | OEM size | OEM size | OEM size | OEM size |
| Valve springs | New standard springs | Upgraded dual springs | Upgraded dual springs | Heat-dispersing coated competition dual springs |
| Plug kit | Included | Included | Included | Included |
| Flow improvement | Flow-verified | Flow-verified | Flow-verified | Flow-verified |
| Deck surface | New CNC finish | New CNC finish | New CNC finish | New CNC finish |
| Install support | Torque specs + lifting straps included | Torque specs + lifting straps included | Torque specs + lifting straps included | Torque specs + lifting straps included |
| Included gasket | — | — | — | Performance fire-ring head gasket included |
| Magnaflux + 60 PSI test | ||||
| Loaded & lash-set | ||||
| Warranty | 12 mo standard | 12 mo standard | 12 mo standard | 12 mo standard* |
Built To Handle More Heat & Pressure
Material strength matters when cylinder pressure, heat cycling and heavy loads go up. JAK'S Stage 3 heads routinely measure in the HT350 range, while Stage 6 steps up to CGI 450 compacted graphite iron for max-output builds.
Quality CheckedBefore It Ships
Every JAK'S Diesel cylinder head is inspected through a controlled process before it ships. We verify the details that matter so your head is ready for real work.
Component
Inspection
Castings and components are checked for quality, fitment and consistency before assembly begins.
Machining &
Assembly Checks
Each head is checked through multiple stages of machining and assembly to verify every critical detail.
Final Test &
Ship Review
Pressure-tested, flow-verified, loaded, lash-set and reviewed for final fit and finish before it ships to your door.
Inspection
Pressure Tested
Verified
Lash-Set
Included
Included
Standard 12-Month Unlimited-Mile Warranty
Every JAK'S Performance head is covered against defects in materials and workmanship — parts and reasonable labor. No mileage cap, no fleet exclusions, no runaround.
How A Claim Works
Not Sure Which Stage You Need?
Tell a JAK'S specialist how you run the truck — they'll spec the right head and cross your casting by hand.