2004.5-2005 GM 2500HD/3500HD 6.6L LLY 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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Industrial PDM-362.040injections Forged .040 Mahle Race Pistons Set | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Industrial PDM-362.040injections Forged .040 Mahle Race Pistons Set | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Industrial Injection

Industrial PDM-362.040injections Forged .040 Mahle Race Pistons Set | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: IISPDM-362.040
$3,199.14
Industrial PDM-362STD Injections Forged Standard Mahle Race Pistons Set | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Industrial PDM-362STD Injections Forged Standard Mahle Race Pistons Set | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Industrial Injection

Industrial PDM-362STD Injections Forged Standard Mahle Race Pistons Set | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: IISPDM-362STD
$3,199.14
Industrial PDM-362.020injections Forged .020 Oversize Mahle Race Pistons Set | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Industrial PDM-362.020injections Forged .020 Oversize Mahle Race Pistons Set | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Industrial Injection

Industrial PDM-362.020injections Forged .020 Oversize Mahle Race Pistons Set | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: IISPDM-362.020
$4,135.06
Industrial PDM-298STD Fly Cut Chamfered & De-Lipped Piston Kit STD | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Industrial PDM-298STD Fly Cut Chamfered & De-Lipped Piston Kit STD | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Industrial Injection

Industrial PDM-298STD Fly Cut Chamfered & De-Lipped Piston Kit STD | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: IISPDM-298STD
$3,845.03
Industrial PDM-298.040 Fly Cut Piston Kit .040 | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Industrial PDM-298.040 Fly Cut Piston Kit .040 | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Industrial Injection

Industrial PDM-298.040 Fly Cut Piston Kit .040 | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: IISPDM-298.040
$2,626.16
Cometic C15376-062 LHS MLX Cylinder Head Gasket - .062 inch Bore 4.130 inch | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Cometic C15376-062 LHS MLX Cylinder Head Gasket - .062 inch Bore 4.130 inch | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Cometic

Cometic C15376-062 LHS MLX Cylinder Head Gasket - .062 inch Bore 4.130 inch | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: COMC15376-062
$195.29
$216.98
SAVE $21.69
Victor Reinz 14-10117-01 Engine Cylinder Head Bolt Set | 2001-2011 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Victor Reinz 14-10117-01 Engine Cylinder Head Bolt Set | 2001-2011 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Victor Reinz

Victor Reinz 14-10117-01 Engine Cylinder Head Bolt Set | 2001-2011 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: VRZ14-10117-01
$71.94
Victor Reinz 71-13629-00 Exhaust Pipe Flange Gasket | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Victor Reinz 71-13629-00 Exhaust Pipe Flange Gasket | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Victor Reinz

Victor Reinz 71-13629-00 Exhaust Pipe Flange Gasket | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: VRZ71-13629-00
$5.01
Victor Reinz 61-36465-20 Engine Cylinder Head Gasket | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Victor Reinz 61-36465-20 Engine Cylinder Head Gasket | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Victor Reinz

Victor Reinz 61-36465-20 Engine Cylinder Head Gasket | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: VRZ61-36465-20
$83.60
Victor Reinz 61-36460-20 Engine Cylinder Head Gasket | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Victor Reinz 61-36460-20 Engine Cylinder Head Gasket | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Victor Reinz

Victor Reinz 61-36460-20 Engine Cylinder Head Gasket | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: VRZ61-36460-20
$80.17
Victor Reinz 02-10484-01 Engine Cylidner Head Gasket Set | 2004-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Victor Reinz 02-10484-01 Engine Cylidner Head Gasket Set | 2004-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Victor Reinz

Victor Reinz 02-10484-01 Engine Cylidner Head Gasket Set | 2004-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: VRZ02-10484-01
$253.06
Wehrli 100158 Heavy Duty Engine Mounts | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Wehrli 100158 Heavy Duty Engine Mounts | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Wehrli 100158 Heavy Duty Engine Mounts | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Wehrli 100158 Heavy Duty Engine Mounts | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Wehrli 100158 Heavy Duty Engine Mounts | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Wehrli Custom Fab

Wehrli 100158 Heavy Duty Engine Mounts | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: WCF100158-GB
From $464.63
Wagler C6643 Dual Valve Spring Kit with Steel Retainers | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Wagler C6643 Dual Valve Spring Kit with Steel Retainers | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Wagler Competition Products

Wagler C6643 Dual Valve Spring Kit with Steel Retainers | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: WCPC6643
$600
Cometic PRO3009T Top End Gasket Kit - 4.100 inch Bore .040 inch | 2004-2007 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Cometic PRO3009T Top End Gasket Kit - 4.100 inch Bore .040 inch | 2004-2007 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Cometic

Cometic PRO3009T Top End Gasket Kit - 4.100 inch Bore .040 inch | 2004-2007 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: COMPRO3009T
$616.36
$662.75
SAVE $46.39
Cometic PRO3008B Bottom End Gasket Set | 2001-2007 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
Cometic PRO3008B Bottom End Gasket Set | 2001-2007 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

Cometic

Cometic PRO3008B Bottom End Gasket Set | 2001-2007 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: COMPRO3008B
$190.85
$205.22
SAVE $14.37
PPE 168030170 Engine Mount Kit 70 Hardness | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
IN STOCK
PPE 168030170 Engine Mount Kit 70 Hardness | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 168030170 Engine Mount Kit 70 Hardness | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 168030170 Engine Mount Kit 70 Hardness | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 168030170 Engine Mount Kit 70 Hardness | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE

PPE 168030170 Engine Mount Kit 70 Hardness | 2001-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: PPE168030170
$269.99
PPE 119030100 Raw 304 Stainless Steel Coolant Tube (Pump to oil cooler) | 2001-2025 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 119030100 Raw 304 Stainless Steel Coolant Tube (Pump to oil cooler) | 2001-2025 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 119030100 Raw 304 Stainless Steel Coolant Tube (Pump to oil cooler) | 2001-2025 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 119030100 Raw 304 Stainless Steel Coolant Tube (Pump to oil cooler) | 2001-2025 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 119030100 Raw 304 Stainless Steel Coolant Tube (Pump to oil cooler) | 2001-2025 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 119030100 Raw 304 Stainless Steel Coolant Tube (Pump to oil cooler) | 2001-2025 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE

PPE 119030100 Raw 304 Stainless Steel Coolant Tube (Pump to oil cooler) | 2001-2025 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: PPE119030100
$197.99
$219.99
SAVE $22
PPE 118026110 Stage 1 Performance Camshaft - Alt Fire | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
IN STOCK
PPE 118026110 Stage 1 Performance Camshaft - Alt Fire | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 118026110 Stage 1 Performance Camshaft - Alt Fire | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 118026110 Stage 1 Performance Camshaft - Alt Fire | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE

PPE 118026110 Stage 1 Performance Camshaft - Alt Fire | 2001-2016 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: PPE118026110
$629.99
PPE 118021423 Valve Cover Kit with out Pillars - Gold | 2004-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
IN STOCK
PPE 118021423 Valve Cover Kit with out Pillars - Gold | 2004-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE

PPE 118021423 Valve Cover Kit with out Pillars - Gold | 2004-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: PPE118021423
$287.99
PPE 118021400 Valve Cover Kit - No Pillars | 2004-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
IN STOCK
PPE 118021400 Valve Cover Kit - No Pillars | 2004-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 118021400 Valve Cover Kit - No Pillars | 2004-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE

PPE 118021400 Valve Cover Kit - No Pillars | 2004-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: PPE118021400
$269.99
PPE 118021222 Valve Cover Kit with Pillars - Blue | 2005-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
IN STOCK
PPE 118021222 Valve Cover Kit with Pillars - Blue | 2005-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE

PPE 118021222 Valve Cover Kit with Pillars - Blue | 2005-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: PPE118021222
$305.99
PPE 118021220 Valve Cover Kit with Pillars - Black | 2005-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
IN STOCK
PPE 118021220 Valve Cover Kit with Pillars - Black | 2005-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 118021220 Valve Cover Kit with Pillars - Black | 2005-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE

PPE 118021220 Valve Cover Kit with Pillars - Black | 2005-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: PPE118021220
$305.99
PPE 118021212 Valve Cover Kit with Pillars - Red | 2005-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
IN STOCK
PPE 118021212 Valve Cover Kit with Pillars - Red | 2005-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 118021212 Valve Cover Kit with Pillars - Red | 2005-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE

PPE 118021212 Valve Cover Kit with Pillars - Red | 2005-2010 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: PPE118021212
$305.99
PPE 114000551 Oil Filter Adapter Threaded 13/16 inch - 16 UNF | 2001-2019 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax
PPE 114000551 Oil Filter Adapter Threaded 13/16 inch - 16 UNF | 2001-2019 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

PPE

PPE 114000551 Oil Filter Adapter Threaded 13/16 inch - 16 UNF | 2001-2019 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax

SKU: PPE114000551
$8.99

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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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