Malibu Hammerhead 383

Malibu Hammerhead 383(click image to enlarge)

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The Hammerhead 383 (400 HP) is the most powerful 6.2L small-block V8 ever developed for inboard use. Its aggressive new appearance matches its 400 horsepower and 420 foot-pounds of torque. Capped with Malibu’s exclusive intake plenum, it sports Indmar’s high flow multi-port induction system, GM’s Fast Burn aluminum heads and GM Performance-spec cam with 1.5:1 roller rockers for less friction, more power.
Not available on Sportster.

Here's a small-block package with the torque and smooth, linear power of a big-block. The Hammerhead 383 has as a standard feature Precision Pro Speed Control© (Malibu's privately labeled version of Indmar's ETC-electronic throttle and cruise-system). The Indmar developed system allows the helm throttle control to electronically connect to the engine's ECM. Throttle response is quick and smooth. The Electronic Throttle Control with Cruise feature is a bonus to recreational water-ski and wakeboard families.


Motor head details start with a 350 CID 5.7L GM Vortec block sporting a 3.8-inch stroke that brings the cubic inches up to 383 (6.2L). Beyond brute power there is built-in toughness like the 4340 nitrided and induction hardened crank (with 4 bolt main) and unique forged powdered metal connecting rods.
Performance features include GM's legendary FastBurn aluminum heads to provide excellent air handling and combustion characteristics along with 9.7:1 compression. Stainless steel valves and retainers are specified for reliable performance at extended RPMs.


For optimal fuel/air delivery, the power plant uses an Indmar custom designed intake manifold with its proven single-plane, tuned runner system. It is teamed with a high-performance cam specifically ground for high lift and long duration. Hydraulic roller lifters are matched to 1.5 to 1 roller rocker arms to round out this machine's beefy valve train.


The performance is enhanced even further with Indmar's exclusive ETX (extreme tuned exhaust) one-piece aluminum exhaust manifolds that boost both horsepower and torque by virtually eliminating backpressure. Add Indmar's custom calibration and the Indmar 6.2L is destined to curl the toes of today's power-hungry consumers.


The Hammerhead's brain is Delphi's most advanced water resistant ECM (Electronic Control Module) the MEFI-5 hardware/software system. The MEFI-5 system is custom calibrated by Indmar to provide maximum performance and drive ability. By custom calibrating the ECM to match hull design requirements and the intended boat application this process allows boat and motor to perform as one seamless unit. The three-dimensional system precisely manages fuel, ignition and air. It is programmed to deliver the power skiers' and wake boarders' need, plus the classic turnkey starts, unhesitating dependability and fuel efficiency that only Indmar can deliver.


Offered as a power option in most 2007 Malibu Boat models, the Indmar inboard is privately labeled as the Malibu Hammerhead 383. Like all Indmar engines, it carries a three-year factory-backed limited warranty, the industry's finest.


Certified: 3-Stars Ultra-Low Emission by California Air Resources Board 2007.
Note: All Malibu Models are available as Salt Water Specific engines.


Experienced saltwater boaters will be the first to appreciate the extensive list of saltwater-specific details found in the Malibu SS series. All marinized parts are E-coated, an advanced electro-coat dip process that provides optimum protection against corrosion. Unlike paints or powder coating, E-coating completely covers both external and internal surfaces, creating a permanent-paint-to-metal bond. Will not peel. Will not crack. Corrosion will not put a dent in it.
SS Cooling systems are totally closed and corrosion free. Saltwater never enters an SS engine system. It uses only propylene-glycol/water coolant driven by a high-flow pump. Coolant tanks are easily accessible for filling and maintenance and are equipped with sacrificial anodes for extended life.
Each Malibu SS engine is protected by the same three-year limited warranty that backs every OEM installed Malibu engine.



General Specifications

  • Displacement: 6.2L / 383 CID
  • Cylinders: V-8
  • Bore & Stroke: 4.00 x 3.8 (stroked from 3.48)
  • Compression Ratio: 9.7:1 (GM FastBurn Aluminum Heads)
  • Exhaust: ETX Tuned Port High-Performance Exhaust System. Fuel System: EFI - custom tuned Indmar designed multi-port induction system
  • ECM: Delphi MEFI-5 hardware/software system that is custom calibrated by Indmar.
  • Ignition: HVS -- High Voltage Switch Ignition System
  • Cam/Valve Train: High-lift and long duration performance cam; hydraulic roller lifters and 1.5 to 1 roller rocker arms.
  • Fuel Required: 89-octane min.
  • Oil Type: Pennzoil Marine (SAE 15W-40) SJ/CG4
  • Oil Capacity: 5.5 quarts with filter
  • Oil Filter: Pennzoil PZ3
  • Spark Pugs: 41-993 (Platinum Tip)
  • Max. RPM: 5,200



Warranty: Factory-Backed 3 year limited warranty including fuel and electrical.
Heavy-Duty Sealed Wiring Harness:
High Output 90-Amp Alternator: Produces 40 amps at idle.

Billet pulleys: water pump and crankshaft.
Marine-Specific Circulating Water Pump Impeller:
Serpentine Alternator and Circulation Water pump Belt:

Advanced Valve Train: Camshaft with marine-specific performance profile increases low end torque for hole-shots, while lengthening the flat torque curve for excellent top end power. Hydraulic roller lifters allow use of fast-action cam lobes to boost power while retaining a quiet idle and reducing friction and wear.