6.6L Long Block Model C LLY Engine 2004.5-2006 – Duramax Diesel Engine

6.6 Duramax Engines built by Choate Engineering Performance. Engineered to outlast the factory engines. Engineered to fix all the flaws of the factory engine. They say the definition of insanity is doing the same thing over and over expecting different results. In other words, you would be insane to purchase another factory engine from GM. Choate Engineering Performance is the most sane option. Machined and Built in the USA.

6.6L Long Block Model C LLY Engine 2004.5-2006 – Duramax Diesel Engine.

• Pressure Test Heads
• Remanufactured Valves
• All New Valve Guides
• Install New Valve Seals
• Test Spring Tension
• New Freeze Plugs
• Keyed Crankshaft

Machining Processes

• Full CNC blue print machining, (bore, deck, hone and line honed)
• The Cylinder bores are blue print bored to a true 90 degrees over the crankshaft center line
• Diamond honed to within .0002 inch for precise piston to cylinder bore clearance.
• Bored and line hone the crank bore housing to precisely align the crankshaft in the engine block.
• The piston diameter measured to the nearest .0001 inch matched to cylinder bores.
• The Cylinder block is surfaced to a finish of RA30 or lower, which meets the factory specification in both flatness and smoothness for the block to head sealing surface.
• This is mandatory for proper sealing of a MLS Gasket.
• Check both wrist pin and crank pin to rod clearances
• New Upgraded Pistons .10 – .30 inch over
• New OE Lifters
• Lifter Guides
• OE Crank Flange Bolts
• Crankshaft is Polished and ground to .0005 concentricity or less
• Camshaft – Polished and Inspected
• New Rod, Main and Cam Bearings

  What you need to know about Choate Vs. the Competition. We have put together a list of videos for all processes we do to this engine. It is your responsibility to educate yourself about the differences.

To do so we made that easier with this compilation of videos!

This is why we machine the crankshaft for an upgraded keyway!

What is Blueprint Boring?

This is why we square deck the block!

Why we only use the Rottler hone for YOUR engine!

Why do we encourage you to buy a long block instead of a short block?

Assembled by Our Professional Team in house.

6.6L Duramax LLY Long Block Model C series engines:  Built to resolve the factory problems. Made to Last. 12/12 Warranty.

• 6.6L 2004.5-2006 Duramax LLY
• Long Block
• Model C Diesel Engine

Daily Driver Upgrades include but are not limited to:

• Balanced Rotational Assembly and Weight Matched
• Torque Plate Honed
• 5 Year 100K Mile Warranty
• Head Studs
• New Harmonic Balancer
• Flywheel