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.

CHOATE Engineering Performance Crate Engine Features:

The Choate 6.6L Duramax Model C is designed to fix all the flaws that are associated with it. Engineered for longevity it uses different machining process and specs than does the factory. It is designed to exceed the performance of the factory engine. It is made for the drivers satisfaction.

This 6.6 engine is backed by our 1-Year Unlimited Mile Warranty, ensuring reliability and peace of mind. To maintain warranty coverage and maximize engine longevity, specific components must be purchased directly from Choate, including the oil pump, oil cooler, water pump, and the necessary gaskets. These Diesel parts are critical to the 6.6 diesel engine’s performance and durability—without them, premature issues may arise.

Please note that this 6.6 Crate Engine does not include:

Oil pan
Rocker assemblies, rockers, rocker hold-downs, or rocker boxes
Pushrods
Injectors, turbos, or any fuel and air-related components
However, we offer these parts separately at highly competitive prices—guaranteed to match or beat any competitor. Get everything you need in one place for a hassle-free installation and long-lasting performance.

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