This upgraded 6.6 Duramax Diesel engine cylinder head is a great choice for an improvement over stock. This listing is for 1 Cylinder Head.

6.6 Duramax LLY Workhorse Plus Cylinder Head Reman
Choate Part Number: CEPLLYWPHR

OE Part number: 97779579
Fitment: 2004,2004.5, 2005

Manufacturer: Choate Engineering Performance

6.6 LLY Workhorse Plus Duramax Remanufactured Diesel Engine Cylinder Heads Include:

• Resurfaced Cylinder Head To Meet Or Exceed OEM Specification of Ra or Roughness Average, which maximizes sealing surface performance.
• Used Cast
• New Valve Stem Seals
• New Valve Guides
• Regrind Valves and inspect margins for proper sealing.
• Cut seats with 3 angles and optimize flow.
• O'ring Machined
• Heavy Duty Valve Springs . 130lb. seat pressure at 1.720 (to the top of the retainer) installed height

Cleaning Process:
Once your 6.6 Workhorse Plus Duramax Diesel Engine cylinder head passes our rigorous inspection for cracks and imperfections through MPI testing, it will go through a stress relieving process in a furnace to turn any grease and oil into ash.

Then we shot blast it in our cabinet to remove any rust and scaling. This will also relax the material before machining to our specifications.
After this, we check it for any broken bolts or studs, and remove them.

Once it has met our stringent standards, it will then start through the machining process.

Machining Process:

Our heads are blueprinted to proprietary valve train geometry, to alter valve height and valve recession for maximum reliability and longevity. Our Valve stem heights are altered to remove preload on the lifter and decrease the wear and help the lifter live a long life.

We O-ring our Workhorse heads to eliminate factory head gasket issues. A receiver groove is machined into the deck surface, and a USA-made stainless steel wire is pressed in, applying extra pressure to the MLS gaskets and sealing combustion pressure.

The durable, reusable high-carbon stainless wire works with standard head gaskets and requires no special block machining-just a clean, dry, flat deck surface.

Inspection Process:

Once our machining processes are complete, we pressure test the 6.6 Duramax cylinder heads with 40 PSI pressure to make sure there are no leaks. Then we send it through another extensive cleaning, quality control inspection and sign off sheet that will include all specs of the heads.
We measure the following specs by use of profilometer:

• Valve recessions
• Stem Heights
• Installed Spring Heights
• Spring Pressures
• Keeper and Lock Positions
• RA Recording

Tech Tip:
Be sure that the surface of the block is inspected and cleaned prior to installation of this Cylinder Head.