LS Engine Parts and Accessories

Extra O2 Bung for LS Marine Aluminum Exhaust Manifold System

The 620-32940 Exhaust System comes with a single O2 Bung, however some systems require a 2nd O2 bung. Order this part alongside a 620-32940 system to have two O2 bungs.

Shift Bracket for LS Marine Aluminum Exhaust Manifold System

Add an Shift bracket to the 620-32940 or 620-32942 LS Exhaust Systems or IMCO LS Exhaust Systems.

ECM Bracket for LT Marine Aluminum Exhaust Manifold System

Add a ECM bracket to the 620-32940 or 620-32942 LT Exhaust Systems or IMCO LT Exhaust Systems.

NOTE: If using with a riser mounted O2 Sensor, modification to bracket will be required or O2 sensor moved inboard.

Replacement Riser Gasket for LS Marine Aluminum Exhaust Manifold System

Replacement Riser Gasket for the 620-32940 or 620-32942 LS Exhaust Systems or IMCO LS Exhaust Systems.

Exhaust Gaskets for LS Marine Aluminum Exhaust Manifold System

Replacement Exhaust Gaskets for the 620-32940 or 620-32942 LS Exhaust Systems or IMCO LS Exhaust Systems. Sold in pairs for one engine.

CMI CMI LS Chevy E-Top Headers, Polished or Satin Finish

• Improved exhaust flow over existing cast manifolds
• Lightweight 316L stainless steel
• Increased fuel efficiency
• Inside port size of 1-5/8", also in 1-7 /8"
• Smooth mandrel bent tubes
• No separate tailpipe required
• Taller custom application options

Note: All CMI Systems are sold without Tailpipes

GM Gen III/IV Small Block V8. LS Series .030" MLS Exhaust Gaskets. - Sold in Pairs

The Cometic Severe Duty Multi Layer Series exhaust gaskets are comprised of three separate layers of stainless steel. Cometic uses stainless steel for increased strength and its ability to rebound from heat compression, plus excellent corrosion resistance. The outer layers of the gasket are embossed and coated. This is designed to meet the demands of a variety of harsh sealing environments, load conditions and surface finishes.

The Severe Duty MLS exhaust gasket is ideal for both aluminum heads & cast iron heads as well as cast iron and aluminum blocks. The composition of MLS gaskets will also withstand the shearing forces created by aluminum heads on cast iron blocks. No re-torque is required and by design promotes an even torque load across the sealing surface.

Sold in Pairs

LS Exhaust Gasket

Sold Each

Holley LS Chevy Valve Covers - Black

Holley's new 2-Piece LS valve covers are a great way to update the look of your LS engine without the use of complicated adapter systems or the hassle of remote coil relocation. These modular LS valve covers feature an OE height, internally baffled LS valve cover base with integrated coil mounts for popular Gen I and Gen V style LS coil bodies, and a vintage style finned overcover that hides the unsightly LS coils and messy wiring harness - allowing the full performance benefits of coil-on-cover ignition setups without the robotic styling. Each modular coil cover features a simplified version of our Vintage Series style fins that seamlessly blends with other finned Holley dress-up accessories such as our LS valley covers and 14" round air cleaners. The coil cover also features cast-in provisions for the spark plug boots and coil wiring harness so no extensions or custom wiring is required.

Each 2-Piece LS valve cover set includes a low-profile billet oil fill cap, hardware and spacers for mounting both versions of LS coil bodies, and 12-point dress up hardware and rubber grommets for the coil covers. These modular LS valve covers are now offered in 5 unique finishes: natural cast, polished, satin black, factory orange, and gloss red (black, factory orange and gloss red sets feature machined fins).

• Cast aluminum 2-Piece LS valve covers designed to mount and hide both Gen I and Gen V style LS coil bodies
• Retain the performance of factory coil-on-cover ignition without the unsightly styling
• Base fits LS1, LS2, LS3, LS6 and LS7 engines with clearance for .750” lift cam with stock style rocker arms
• Base features internally baffled ventilation system
• Coil cover features Holley vintage style fins and cast-in wiring provisions
• No coil relocation, wire harness extensions, or custom spark plug wires required
• Includes low-profile billet oil fill cap
• Includes all necessary coil mounting and dress-up hardware

Holley LS Chevy Valve Covers - Polished

Holley's new 2-Piece LS valve covers are a great way to update the look of your LS engine without the use of complicated adapter systems or the hassle of remote coil relocation. These modular LS valve covers feature an OE height, internally baffled LS valve cover base with integrated coil mounts for popular Gen I and Gen V style LS coil bodies, and a vintage style finned overcover that hides the unsightly LS coils and messy wiring harness - allowing the full performance benefits of coil-on-cover ignition setups without the robotic styling. Each modular coil cover features a simplified version of our Vintage Series style fins that seamlessly blends with other finned Holley dress-up accessories such as our LS valley covers and 14" round air cleaners. The coil cover also features cast-in provisions for the spark plug boots and coil wiring harness so no extensions or custom wiring is required.

Each 2-Piece LS valve cover set includes a low-profile billet oil fill cap, hardware and spacers for mounting both versions of LS coil bodies, and 12-point dress up hardware and rubber grommets for the coil covers. These modular LS valve covers are now offered in 5 unique finishes: natural cast, polished, satin black, factory orange, and gloss red (black, factory orange and gloss red sets feature machined fins).

• Cast aluminum 2-Piece LS valve covers designed to mount and hide both Gen I and Gen V style LS coil bodies
• Retain the performance of factory coil-on-cover ignition without the unsightly styling
• Base fits LS1, LS2, LS3, LS6 and LS7 engines with clearance for .750” lift cam with stock style rocker arms
• Base features internally baffled ventilation system
• Coil cover features Holley vintage style fins and cast-in wiring provisions
• No coil relocation, wire harness extensions, or custom spark plug wires required
• Includes low-profile billet oil fill cap
• Includes all necessary coil mounting and dress-up hardware

NOTE: THESE ARE RAW FINISH

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. Sea Pump #625-4117 will not work with these brackets.

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.

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.

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.

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.

NOTE: Will not work with port side mounted sea pumps 625-4116, 625-4117.

These will NOT work with IMCO, MP, or front inlet exhaust systems.
These WILL work with Seaward, Hardin Cyclone, Lightning and CMI exhaust systems

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.

WARNING**** will not work with Variable Valve Timing covers.

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

USCG Approved (SAE J1171)