2004.5-2005 GM 2500HD/3500HD 6.6L LL Duramax Engine & Performance

2004.5-2005 GM 2500HD/3500HD 6.6L LLY Duramax Crate Engines

Crate Engines

2004.5-2005 GM 2500HD/3500HD 6.6L LLY Duramax Gaskets, Gasket Kits & Bearings

Gaskets

2004.5-2005 GM 2500HD/3500HD 6.6L LLY Duramax Glow Plugs

Glow Plugs

2004.5-2005 GM 2500HD/3500HD 6.6L LLY Duramax Head Studs & Main Studs

Head Studs & Main Studs

2004.5-2005 GM 2500HD/3500HD 6.6L LLY Duramax Heads & Valve Train

Heads & Valve Train

2004.5-2005 GM 2500HD/3500HD 6.6L LLY Duramax Motor Mounts

Motor Mounts

2004.5-2005 GM 2500HD/3500HD 6.6L LLY Duramax Oil Pans

Oil Pans

2004.5-2005 GM 2500HD/3500HD 6.6L LLY Duramax Radiators & Cooling Upgrades

Radiators & Cooling Upgrades

2004.5-2005 GM 2500HD/3500HD 6.6L LLY Duramax Rebuild Kits & Internal Parts

Rebuild Kits & Internal Parts

2004.5-2005 GM 2500HD/3500HD 6.6L LLY Duramax Rods, Pistons, Cams & More

Rods/Pistons/Cams & More

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Merchant 10001 Transfer Case Pump Upgrade Kit | 2001-2007 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Merchant 10001 Transfer Case Pump Upgrade Kit | 2001-2007 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Merchant Automotive

Merchant 10001 Transfer Case Pump Upgrade Kit | 2001-2007 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: MAT10001
$77.63
Wehrli 100699 Billet Heater Core Fitting with Hose | Universal
Wehrli 100699 Billet Heater Core Fitting with Hose | Universal
Wehrli 100699 Billet Heater Core Fitting with Hose | Universal

Wehrli Custom Fab

Wehrli 100699 Billet Heater Core Fitting with Hose | Universal

SKU: WCF100699
$75.66
SoCal Diesel 917371 Super Damper Diesel Harmonic Balancers | 2001-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
SoCal Diesel 917371 Super Damper Diesel Harmonic Balancers | 2001-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
SoCal Diesel 917371 Super Damper Diesel Harmonic Balancers | 2001-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SoCal Diesel

SoCal Diesel 917371 Super Damper Diesel Harmonic Balancers | 2001-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: SLD917371
$464.31
Fleece FPE-61-10002-P Cylinder Head (Passenger Side) | 2004.5-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LLY
Fleece FPE-61-10002-P Cylinder Head (Passenger Side) | 2004.5-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LLY

Fleece Performance Products

Fleece FPE-61-10002-P Cylinder Head (Passenger Side) | 2004.5-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LLY

SKU: FLCFPE-61-10002-P
$1,199
Fleece FPE-61-10002-D Cylinder Head (Driver Side) | 2004.5-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LLY
Fleece FPE-61-10002-D Cylinder Head (Driver Side) | 2004.5-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LLY

Fleece Performance Products

Fleece FPE-61-10002-D Cylinder Head (Driver Side) | 2004.5-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LLY

SKU: FLCFPE-61-10002-D
$1,099
BD Diesel 1057735 Throttle Sensitivity Booster | 2001-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
BD Diesel 1057735 Throttle Sensitivity Booster | 2001-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

BD Diesel

BD Diesel 1057735 Throttle Sensitivity Booster | 2001-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: BDD1057735
$283.95
PPE 114025405 PCV Crankcase Breather Filter Kit | 2004.5-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LLY
PPE 114025405 PCV Crankcase Breather Filter Kit | 2004.5-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LLY

PPE

PPE 114025405 PCV Crankcase Breather Filter Kit | 2004.5-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LLY

SKU: PPE114025405
$359.99
Tuner DT1120010101009 Switch on the Fly Tune incl EFI Live Spade | 2004.5-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LLY
Tuner DT1120010101009 Switch on the Fly Tune incl EFI Live Spade | 2004.5-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LLY

Duramax Tuner

Tuner DT1120010101009 Switch on the Fly Tune incl EFI Live Spade | 2004.5-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LLY

SKU: DMTDT1120010101009
$1,140
Edge 21501-3 Juice with Attitude CTS3 | 2004.5-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LLY
Edge 21501-3 Juice with Attitude CTS3 | 2004.5-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LLY
Edge 21501-3 Juice with Attitude CTS3 | 2004.5-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LLY

Edge Products

Edge 21501-3 Juice with Attitude CTS3 | 2004.5-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax LLY

SKU: EDG21501-3
$1,349.95
PPE 118021455 Valve Cover Kit w/o Accessory Mounting | 2004-2010 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax
PPE 118021455 Valve Cover Kit w/o Accessory Mounting | 2004-2010 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax
PPE 118021455 Valve Cover Kit w/o Accessory Mounting | 2004-2010 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax
PPE 118021455 Valve Cover Kit w/o Accessory Mounting | 2004-2010 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax

PPE

PPE 118021455 Valve Cover Kit w/o Accessory Mounting | 2004-2010 GM Sierra/Silverado 2500HD/3500HD 6.6L Duramax

SKU: PPE118021455
$287.99
$319.99
Wagler C6658 Street Girdle | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Wagler C6658 Street Girdle | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Wagler Competition Products

Wagler C6658 Street Girdle | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: WCPC6658
$850
PPE 119024100 Upper & Lower Coolant Hose Kit - Yellow | 2001-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 119024100 Upper & Lower Coolant Hose Kit - Yellow | 2001-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE

PPE 119024100 Upper & Lower Coolant Hose Kit - Yellow | 2001-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: PPE119024100
$269.99
PPE 114025010 Check Valve Crankcase Breather Filter Kit | 2004.5-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 114025010 Check Valve Crankcase Breather Filter Kit | 2004.5-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE

PPE 114025010 Check Valve Crankcase Breather Filter Kit | 2004.5-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: PPE114025010
$44.99
PPE 114010000 Oil Centrifuge Filtration Kit | 2001-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 114010000 Oil Centrifuge Filtration Kit | 2001-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE

PPE 114010000 Oil Centrifuge Filtration Kit | 2001-2005 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: PPE114010000
$449.99
Merchant 98045057 Grade C Right Head Gasket | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Merchant 98045057 Grade C Right Head Gasket | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Merchant Automotive

Merchant 98045057 Grade C Right Head Gasket | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: MAT98045057
$99.72
Industrial 449E01 Stage 1 Pushrods | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Industrial 449E01 Stage 1 Pushrods | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Industrial Injection

Industrial 449E01 Stage 1 Pushrods | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: IIS449E01
$29.05
Wehrli 100442 Billet Oil Fill Tube Cap - Clear Anodized | 2001-2026 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Wehrli 100442 Billet Oil Fill Tube Cap - Clear Anodized | 2001-2026 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Wehrli 100442 Billet Oil Fill Tube Cap - Clear Anodized | 2001-2026 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Wehrli 100442 Billet Oil Fill Tube Cap - Clear Anodized | 2001-2026 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Wehrli 100442 Billet Oil Fill Tube Cap - Clear Anodized | 2001-2026 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Wehrli Custom Fab

Wehrli 100442 Billet Oil Fill Tube Cap - Clear Anodized | 2001-2026 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: WCF100442
$51.41
Wagler CRC6.6ST Street Fighter Connecting Rods | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Wagler CRC6.6ST Street Fighter Connecting Rods | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Wagler CRC6.6ST Street Fighter Connecting Rods | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Wagler Competition Products

Wagler CRC6.6ST Street Fighter Connecting Rods | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: WCPCRC6.6ST
$1,950
PPE 314030212 Oil Cooler Gasket Kit | 2003-2007 Ford F250/F350 6.0L Powerstroke
PPE 314030212 Oil Cooler Gasket Kit | 2003-2007 Ford F250/F350 6.0L Powerstroke

PPE

PPE 314030212 Oil Cooler Gasket Kit | 2003-2007 Ford F250/F350 6.0L Powerstroke

SKU: PPE314030212
$35.99
PPE 168030140 Engine Mount Kit 40 Hardness | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 168030140 Engine Mount Kit 40 Hardness | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 168030140 Engine Mount Kit 40 Hardness | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 168030140 Engine Mount Kit 40 Hardness | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 168030140 Engine Mount Kit 40 Hardness | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE

PPE 168030140 Engine Mount Kit 40 Hardness | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: PPE168030140
$269.99
PPE 149000124 Heat/Sound Insulator Firewall - Gold | 1999-2007 GM Silverado/Sierra
PPE 149000124 Heat/Sound Insulator Firewall - Gold | 1999-2007 GM Silverado/Sierra
PPE 149000124 Heat/Sound Insulator Firewall - Gold | 1999-2007 GM Silverado/Sierra
PPE 149000124 Heat/Sound Insulator Firewall - Gold | 1999-2007 GM Silverado/Sierra

PPE

PPE 149000124 Heat/Sound Insulator Firewall - Gold | 1999-2007 GM Silverado/Sierra

SKU: PPE149000124
$269.99
PPE 128059160 Neodymium Magnet - Ring Style | 2001-2019 Allison 1000
PPE 128059160 Neodymium Magnet - Ring Style | 2001-2019 Allison 1000
PPE 128059160 Neodymium Magnet - Ring Style | 2001-2019 Allison 1000
PPE 128059160 Neodymium Magnet - Ring Style | 2001-2019 Allison 1000

PPE

PPE 128059160 Neodymium Magnet - Ring Style | 2001-2019 Allison 1000

SKU: PPE128059160
$13.49
PPE 118026010 Stage 1 Performance Camshaft - Standard Fire | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 118026010 Stage 1 Performance Camshaft - Standard Fire | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 118026010 Stage 1 Performance Camshaft - Standard Fire | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 118026010 Stage 1 Performance Camshaft - Standard Fire | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE

PPE 118026010 Stage 1 Performance Camshaft - Standard Fire | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: PPE118026010
$629.99
$699.99
PPE 118021418 Valve Cover Kit with out Pillars | 2004-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 118021418 Valve Cover Kit with out Pillars | 2004-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE

PPE 118021418 Valve Cover Kit with out Pillars | 2004-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: PPE118021418
$287.99

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DIESEL TRUCK EXPERTS STANDING BY

The 6.6L Duramax LLY under the hood of your 2004.5-2005 GM Sierra/Silverado 2500/3500 may be one of the best and most efficient engines out there, but even the toughest trucks have some power and performance waiting to be unleashed through various performance modifications. Here at Alligator Performance, we carry a selection of cold air intakes, tuners, fuel upgrades, and turbo upgrades to help you get the most out of your diesel engine. Many of these upgrades like the cold air intakes and fuel upgrades even help promote component longevity so you can enjoy long-lasting and consistent performance without compromise. After you've added a few engine upgrades to your custom build, be sure to check out our premium 2004.5-2005 GM 6.6L Duramax LLY Transmission Upgrades to compliment the increase in power you're throwing down! GM Duramax Fitments: 2004, 2005 GM 6.6L Duramax. Submodel Fitments: WT, Custom, LT, LTZ, High Country, 1LT, 2LT, Pro, SLE, SLT, AT4, Denali. Some exceptions apply, please see individual product pages for specific fitments.

GM Duramax>2004.5-2005 6.6L LLY
Tuners & Monitors
Cooling Upgrades
Head Studs & Main Studs
Rods, Pistons & Cams
Heads & Valve Train

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