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LS Engine Parts and Accessories

LS Jet Boat Rail Kit
Your Price:
$329.99

LS​ Retro-Fit Engine Mount​s for Mercuiser Applications

625-8545

GM LS Marine engine conversions have grown at a speed no one could have gauged until now. Hardin Marine has been at the forefront of the LS marine engine movement for the past number of years bringing to market a cooling system and exhaust option.

But one hurdle of the engine swap on popular Bravo/Alpha applications has left boaters to fend for themselves on solutions or makeshift homegrown engine mount remedies. So the folks at Hardin took to build a direct replacement engine block mount that allows a popular GM LS1, LS2, LS3 to be dropped right back onto the OEM Stud factory mount or the High Performance Hardin Marine stud mount #620-52380.


LS Jet Boat Rail Kit
Your Price:
$798.95

Marine GM LS Engine Swap System for Jet Boat Applications

625-8536

Marine GM LS Engine Swap System for Jet Boat Applications

The GM LS based engine family has already dominated the automotive industry and has quickly become the high performance standard in the performance boating world. Hardin Marine has taken the guess work out of this by developing the most versatile and complete LS Marine engine swap components found anywhere. Making installing a LS in your favorite boat a reality.

The GM LS 1,2,3, and 6 series engines can use this Solid Works/CAD engineered engine swap system for the mounting of a GM LS series engine into a popular Jet driven power boat. The engine mounting swap rail Kit is perfect for the boater that wants to make the switch to modern efficient engines.

Manufactured from 6061 T-6 aluminum and CNC machined from 3/8" thick motor mounts are 26" wide and have an (optional) provision for a alternator mount. The engine mounts sit on top of heavy duty 2-1/2" wide aluminum stringer rails, Comes complete with fasteners.

Note: Spun aluminum flywheel cover, PTO adapter are sold separately.


LS Jet Boat Rail Kit
Your Price:
$589.99

Marine GM LS Engine Front and Rear Mounting Plates

625-8546

Marine GM LS Engine Front and Rear Mounting Plates

The GM LS based engine family has already dominated the automotive industry and has quickly become the high performance standard in the performance boating world. These brackets make installing a LS in your favorite boat a reality.

The GM LS 1,2,3, and 6 series engines can use these Solid Works/CAD engineered engine mounting brackets. These engine mounts are perfect for the boater that wants to make the switch to modern efficient engines.

Manufactured from 6061 T-6 aluminum and CNC machined from 3/8" thick motor mounts are 26" wide and have an (optional) provision for a alternator mount.

Note: These are mounting plates only. No other hardware is included.


Big Block Chevy Closed Cooling Kit Up To 650HP
Starting From:
$1,299.99

This Part has options, please click the button below to order.

GM LSA Closed Cooling System for Engine and Intercooler

625-458 + Option(s)

These are the same coolers OEM Engine manufactures use on their LSA Marine engine conversions. The OEM manufacturer builds their own bracketry and it IS NOT available. So if you plan on buying these units each has a mounting bolt pad but you will need to build YOUR OWN bracketry. If you do not understand closed cooling seek a professional engine builder. There is NOT additional specs available what you see is what we sell we have attached plumbing instructions and some diagrams to assist. They are sold as tanks ONLY for both the engine and the intercooler. Seek a knowledgeable professional for installation.


Big Block Chevy Closed Cooling Kit Up To 650HP
Your Price:
$1,599.99

LS1, LS2, LS3 and LS6 Closed Cooling Kit - Copper / Brass

625-4574

LS1, LS2, LS3 and LS6 Closed Cooling Kit - Copper / Brass

While there are numerous universal OEM closed cooling kits, this is not one of those. This is a true custom engineered and developed closed cooling system designed around new LS1, LS2, LS3 and LS6 applications. The kit is perfect for engines making up to 650 horsepower.

We offer the closed cooling tank version with a pre-primed coat, where you can paint-to-finish. This allows you to customize it to your engine for the ultimate in appearance and durability. This High Performance Closed Cooling kit is designed for applications with horsepower levels to 650HP.

The Kit comes with: Tank, Brackets, Hoses, and Thermostat Housing.


GM LS Series Engine Dual Stage Sea Water Pump
Your Price:
$1,199.99

GM LS Series Engine Dual Stage Sea Water Pump

625-4117

Hardin Marine is the first to bring a engine specific sea water pump for the popular LS series of engines. This dual stage sea water pump was designed around the 5.3 ,6.0, and 6.2 liter generation engine platforms. The pump uses Hardin Marine's Extreme Lifetime Series stainless steel impeller housing as well as a proprietary short body construction that allows the necessary access or clearance for the engines factory engine mounting pads when the pump is installed. The pump is designed to mount to the engine blocks factory A/C mounting bosses while positioning the billet aluminum serpentine pulley in line with OEM crankshaft pulley. The billet mounting bracket provides the two necessary idlers that allow this pump to be incorporated into most factory automotive serpentine accessory drive systems. The Sea pump features female 1" NPT inlet and outlet ports for ease of plumbing convenience.

Note: Fits OEM GM LS Corvette / CTS-V / G8 automotive balancer spacing with 1-1/2" offset (NOT Truck or F-Body balancer)

LS Sea Pump Assembly
Your Price:
$895.99

GM LS Series Engine Single Stage Sea Water Pump

625-4116

Hardin Marine is the first to bring a engine specific sea water pump for the popular LS series of engines. This single stage sea water pump was designed around the 5.3 ,6.0, and 6.2 liter generation engine platforms. The pump uses Hardin Marine's Extreme Lifetime Series stainless steel impeller housing as well as a proprietary short body construction that allows the necessary access or clearance for the engines factory engine mounting pads when the pump is installed. The pump is designed to mount to the engine blocks factory A/C mounting bosses while positioning the billet aluminum serpentine pulley in line with OEM crankshaft pulley. The billet mounting bracket provides the two necessary idlers that allow this pump to be incorporated into most factory automotive serpentine accessory drive systems. The Sea pump features female 1" NPT inlet and outlet ports for ease of plumbing convenience.

Note: Fits OEM GM LS Corvette / CTS-V / G8 automotive balancer spacing with 1-1/2" offset (NOT Truck or F-Body balancer)

LS Crossover and Thermostat
Your Price:
$399.99

GM LS1 - LS3 Thermostatic Control Crossover Cooling System for Non-Circulating Pump Applications

625-4535

GM LS1 - LS3 Thermostatic Control Crossover Cooling System for Non-Circulating Pump Applications

AT last a cooling system solution for adapting the popular GM LS engine into any Jet Boat or application with an external water pump source. This system allows removal of the Automotive engine mounted water circulation pump and provides both water inlet/outlet and temperature control through the integrated thermostat assembly. Clean, simple, and reliable the perfect solution for retrofitting the LS modern engine into a jet boat or any boat not utilizing the OEM circulating pump.


High Performance 1.4KW LS marine starter
Your Price:
$269.99

High Performance LS Marine Starter

620-3121

This is a "TRUE" High Performance 1.4KW LS marine starter designed for use on late model GM LS Chevrolet marine engine application including 4.8,5.3,6.0,6.2, and 7.0 Litre versions. The application has a slight off-set and uses the OE bolts for installation and features Genuine precision N.D starter motor coupled to patented design billet mount.

Technical specs:
  • Rotation CW
  • kW 1.4
  • Gearing 4.44 to 1
  • Rotatable Yes
  • Voltage 12v

USCG Approved (SAE J1171)


Holley LS Hi-Ram EFI Manifold
Your Price:
$791.99

Holley LS Hi-Ram EFI Manifold

710-300-124

Holley LS Hi-Ram EFI Manifold

  • Runner Length – 6.29”, As-Cast Runner Cross-Sectional Area – Tapered 4.67in² to 2.84 in²
  • Throttle Body Flange Location, with 92/102mm EFI Plenum Top : Height – 8.42” (from engine block lifter valley cover flange), Longitudinal Location – 3.84” (forward from engine block front flange), Angle – 25 deg. (down from vertical)
  • Plenum Top Gasket Type – 3/32” Round O-ring Cord
  • Mounting Flange Gasket Type – Standard LS3 Molded O-Ring
  • Port Size – 2.49” Height x 1.21” Wide
  • Total Height with 92/102mm EFI Plenum Top – 12.32” to the lifter valley cover flange on engine block.
  • Base Plenum Top Mounting Flange Height – 8.42” to the lifter valley cover flange on engine block.
These parts should be used for the following applications: Racing/Performance/Street Rodder where hood restrictions are NOT a consideration. Top can be mounted forward or backward. Holley EFI LS main harnesses have a map sensor connecter designed for use with an LS1/2 style map sensor. The 558-416 is an adapter harness that can be used to adapt any LS harness that uses a LS1/2 MAP sensor connection to a LS3 MAP, which is recommended for this manifold.

LS Crossover and Thermostat
Your Price:
$389.99

GM LS1 - LS3 Thermostatic Cooling System for Freshwater Sterndrive Applications

625-4530

GM LS1 - LS3 Thermostatic Cooling System for Freshwater Sterndrive Applications

As Hardin Marine continues the quest towards new product development they have designed an easy to install thermostatic cooling system for freshwater raw water cooled engine applications. This system allows use of an OEM circulating style water pump and multiple accessory drive kits to to be used while providing the necessary thermostat assembly for temperature control. This is perfect for retrofitting a GM LS based engine into most popular sterndrive engine applications using a sea water pump assembly. Precision CNC machined and anodized satin finish make for an attractive compact fitment. Each unit features a 160 degree thermostat while other heat range thermostats and a bypass hose assembly is sold separately.


GM LS Series, Rear Sump Swap Oil Pan
Your Price:
$314.99

GM LS Series, Rear Sump Swap Oil Pan

740-20145

GM LS Series, Rear Sump Swap Oil Pan

Wet Sump, 5 Quart Capacity, 5'5" Deep, 8.5" Wide, 8.375" Long
Engine Application: GM LS Series
Fits: LS Engine Conversions that require a Rear Sump
1/2"-20 drain plug

  • Oil pan has a thick precision laser cut steel rail with a durable fabricated steel sump plated with a clear zinc finish
  • Fabricated, durable steel construction is more adaptable to add fittings, change finishes and weighs les than cast aluminum construction.
  • Clears 4.25" stroke with most steel rods
  • Front of the oil pan is 1.813" Deep to the beginning of the 5.5" deep sump.
  • The fabricated steel sump is 5.5" Deep, 8.5" Wide, and 8.375" Long
  • Removable anti-slosh baffle
  • Features a billet aluminum adapter that allows a 13/16" thread Moroso or OEM oil filter to be mounted in the stock location, no need to run a remote oil filter.
  • Designed to be used with Moroso 740-24050 Oil Pump Pickup
  • Magnetic drain plug and uses a stock dipstick

GM LS Series Remote Oil Filter Adapter
Your Price:
$92.99

GM LS Series Remote Oil Filter Adapter

740-23688

GM LS Series Remote Oil Filter Adapter

  • Replaces Moroso Spin-On oil filter adapter on Moroso #'s 20142, 20143 & 20151 oil pans, comes standard on Moroso # 20146 oil pan.
  • Ideal when chasis restrictions don't allow the use of block mounted filter or when a larger external filter is desires.
  • Billet aluminum construction
  • -10 AN "In" and "Out" ports
  • Includes mounting hardware and engine block sealing O-Rings

GM LS Series Remote Oil Filter Adapter
Your Price:
$99.99

GM LS Series Remote Oil Filter Adapter - 90 Degree

240-22-632

GM LS Series Remote Oil Filter Adapter - 90 Degree

This billet aluminum adapter is designed to install under the pan rail of  LS1 pans and provide inlet and outlet ports for installing lines to a remote oil filter. Adapter features o-ring seals between the pan and the adapter and 1-1/16" -12 AN oil inlet and outlet ports.

  • 1/2 NPT Inlet and Outlet 
  • Ports are set at 90 Degrees
  • Lightweight Billet Design

Hardin Billet Aluminum Flywheel GM (LS1-LS7)
Your Price:
$325.99

Hardin Billet Aluminum Flywheel GM (LS1-LS7)

755-8644

Hardin Billet Aluminum Flywheel GM (LS1-LS7)

Ring Gear Tooth Quantity:168-tooth, Rear Main Seal Style:1-piece, Flywheel Material:Aluminum

These precision billet aluminum flywheels deliver all of the strength and reliability that you desire with the light weight and advantages that only aluminum can provide. Lightweight Aluminum alloy flywheels can offer substantial benefits for certain situations such as light weight boats or racing boats that need rapid engine rpms instantaneously. These are recommended as replacements for factory-cast flywheels in high performance and racing applications. They're better for acceleration of heavier race boats. All Hardin flywheels are CNC-machined from certified materials.

  • Accepts Mercury couplers and heavy duty drive plates
  • Multi-point ring gear attachment
  • Light weight yet durable
  • Zero/neutral balance • 168 tooth gear
  • Bottom Mount Starter Flywheel

Hardin Steel Billet Flywheel GM (LS1-LS7)
Your Price:
$295.99

Hardin Steel Billet Flywheel GM (LS1-LS7)

755-8643

Hardin Steel Billet Flywheel GM (LS1-LS7)

Ring Gear Tooth Quantity:168-tooth, Rear Main Seal Style:1-piece, Flywheel Material:Steel

These precision steel flywheels deliver all of the strength and reliability that you need in a performance application) Cast flywheels are porous units designed for low rpm truck and industrial applications) Steel provides a shatter free strength that could mean the difference between ripping your boat in half under way. These neutrally balanced units drilled to accept popular Mercruiser high Performance couplers.

  • Accepts Mercury couplers and heavy duty drive plates
  • Multi-point ring gear attachment
  • Zero/neutral balance • 168 tooth gear
  • Bottom Mount Starter Flywheel

Power Take Off Adapter - LS1 Chevy 1310 Flexplate
Your Price:
$99.99

Power Take Off Adapter - LS Chevy 1310 Flexplate

500-2000

Power Take Off Adapter - LS Chevy 1310 Flexplate

Uses 3/8-24 bolts on 2" x 2-3/8" centers

These flanges bolt on the flywheel or flexplate and accept 1310 spicer drivelines.  There are many more available, just call us. These power take offs are needed when attaching your drive shaft to your engine.


Power Take Off Adapter - LS1 Chevy 1310 Flywheel
Your Price:
$99.99

Power Take Off Adapter - LS Chevy 1310 Flywheel

500-2005

Power Take Off Adapter - LS Chevy 1310 Flywheel

Uses 3/8-24 bolts on 2" x 2-3/8" centers

These flanges bolt on the flywheel or flexplate and accept 1310 spicer drivelines.  There are many more available, just call us. These power take offs are needed when attaching your drive shaft to your engine.


Power Take Off Adapter - LS Chevy 1350 Flexplate
Your Price:
$110.99

Power Take Off Adapter - LS Chevy 1350 Flexplate

500-2010

Power Take Off Adapter - LS Chevy 1350 Flexplate

Uses 7/16-20 bolts on 2-3/8" x 2-7/8" centers

These flanges bolt on the flywheel or flexplate and accept 1350 spicer drivelines.  There are many more available, just call us. These power take offs are needed when attaching your drive shaft to your engine.


Power Take Off Adapter - LS Chevy 1350 Flywheel
Your Price:
$110.99

Power Take Off Adapter - LS Chevy 1350 Flywheel

500-2015

Power Take Off Adapter - LS Chevy 1350 Flywheel

Uses 7/16-20 bolts on 2-3/8" x 2-7/8" centers

These flanges bolt on the flywheel or flexplate and accept 1350 spicer drivelines.  There are many more available, just call us. These power take offs are needed when attaching your drive shaft to your engine.