Mercruiser 8.1L 496 Horizon Inboard

Short description:

Mercruiser 8.1L 496 Horizon Inboard


1 year Mercruiser Warranty


Mercruiser Remanufactured 8.1L 496 Horizon Inboard

Mercruiser offers this remanufactured "turn-key" 8.1L 496 Horizon Inboard marine engine to replace 7.4L, 8.1L, and 8.2L inboard applications. This is the ideal big block repower for your inboard yacht.



375 HP (272 kW)

Full Throttle Range

4200-4600 RPM


CID 496 (8.1L)

Engine Type

Remanufactured GM 8.1L Block & Heads

Bore & Stroke

4.25” x 4.38” (108mm x 111mm)

Compression Ratio

9.1:1 with Hypereutectic Pistons

Rocker Arm Ratio

1.7:1 Stamped Steel

Fuel Requirement

87 Octane (R+M)/2

Engine Control System 

PCM 555

Fuel Delivery System

Gen III Cool Fuel

Fuel Injection System

Sequential Multi-Point Electronic Fuel Injection

Induction System

 2-piece Long Runner Intake with 75mm Throttle Body

Ignition System

Distributorless Ignition w/Knock Control & Platinum Spark Plugs

Charging System

65 Amp/917 Watt Alternator

Water Drain System

Single Point - Air Actuated

Exhaust System

Iron Manifolds with 4" Diameter 316 SS Dry Joint Exhaust Elbows, +2" Risers Standard with these models

Cooling System

Closed Cooling, Long Life 5-year Antifreeze, Brass Sea Water Pump

Accessory Drive System

Serpentine Belt

Lubrication System

High Flow Oil Pump and Copper Engine Oil Cooler

Recommended Engine Oil

SAE 25-40 NMMA Certified FC-W Synthetic Blend

Audio Warning System

Oil Pressure, Coolant Temperature, Drive Lube, Exhaust Manifold Temperature, Sea Water Pressure,

Low Voltage, Over-Rev Control, Knock Control

Transmission Coupler

Dual-Stage Coupler - must be changed for 72C transmissions

Dimensions (LxWxH)

47" x 33" x 24"

Engine Weight

1131 lbs

Boat Harness Type


Our Shipping Policy


We ship our engines all over the world. In the domestic US, we ship via FedEx Freight, although on occasion other freight carriers may be used. We usually need a 1 business day handling time on our engines. Please give us a call at 877-639-2881 or by email at to request a shipping quote.

Our standard shipping cost is shipping to a business location or to the closest freight terminal to you. A list of Fedex Freight terminals can be found here

Residential Delivery with liftgate adds $75 to the shipping cost.


Our engines have been shipped all over the world. We usually ship via ocean and air freight depending on how much of a rush our customers are in. To request a shipping quote please email us at with the following information:

  • item part #
  • desination country and postal code

We'll get back to you quickly with a shipping quote!

Customers also bought

Huge Selection of Parts and Engine Components