8.1L Horizon

370 Crankshaft Horsepower

8.1L Horizon

The ideal big-block repower for your inboard yacht. This is the ideal replacement inboard engine for any make of 7.4, 454, 8.2, 502 or 8.1 engines that power twin-engine inboard boats.

3-Year Factory Warranty

Available when purchased through any Mercury/MerCruiser authorized dealer

Engine only – transmissions must be purchased separately.



Part Number V-Drive 8M0052317
Inline 8M0052318
Horsepower @ flywheel 370
Kilowatts @ flywheel 272
Maximum RPM (WOT) 4200-4600
Engine Type GM V-8 remanufactured iron marine block
Bore & Stroke (in/mm) 4.28 x 3.48 in
109 x 111 mm
Compression Ratio 9.1:1
Fuel / Ethanol Tolerance 87 octane / up to 10% ethanol
Engine Control System PCM 555 w/knock control & crankshaft trigger
Fuel Delivery System GEN III cool fuel
Fuel Injection System / Carburetor Type Sequential multi-point electronic fuel injection (MPI)
Induction System Two-piece long runner intake with 75mm throttle body
Charging alternator amp 65
Charging alternator watt 917
Water drain system Single-point air drain
Exhaust System Electro-deposition paint coated warm iron manifold with 316 stainless dry joint elbow and 2” risers standard
Cooling System 160F closed cooling
Accessory Drive System Serpentine belt
Lubrication System High flow 60 psi oil pump with copper oil cooler
Recommended Oil Mercury MerCruiser Synthetic Blend 25W-40, NMMA FC-W rated
Pistons Cast hypereutectic alloy
Cranktrain Powder metal rods and nodular iron crankshaft
Rocker Arms 1.7:1 stamped steel
Length (in/mm) 32in / 814mm when installed with transmission
Width (in/mm) 33in / 854mm
Height (in/mm) 24in / 607mm
Weight (lbs/kg) 1130lbs / 513kg when installed with transmission
Features & Related Products Analog Controls
Analog Gauges
Digital Gauges
Remote Oil filter
SmartCraft Digital Technology
Compatible Drives (Application Dependant - Contact Sales or Service) ZF 80A
ZF 63A
VD 5000A
VD 5000V
VD 72C – requires spring plate
ZF 63C – requires spring plate

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