966-9451A2 Mercruiser Cylinder Head | Genuine Used Part

🔧 Product Description

Genuine MerCruiser 3.7L Four-Cylinder Cylinder Head Assembly - Part Number: 966-9451A2

A genuine used MerCruiser cylinder head for selected 3.7-litre 165HP to 190HP four-cylinder petrol marine engines.

This cast-iron cylinder head is used on the MerCruiser 470-series engine family and carries the intake and exhaust valves, rocker gear, spark plugs and combustion chambers.

⚙️ Key Features

• Genuine used MerCruiser 3.7L cylinder head
• Correct assembly part number 966-9451A2
• Cross-references with earlier head 966-6187A1
• Fits the aluminium-block MerCruiser 470 engine family
• Suitable for professional inspection or valve servicing before installation

🚤 Compatibility

Commonly used on

• MerCruiser 3.7-litre four-cylinder petrol engines
• MerCruiser 470-series sterndrive packages

Typically suits

• Engine models:
• MerCruiser 165
• MerCruiser 170
• MerCruiser 180
• MerCruiser 190
• MerCruiser 470
• MerCruiser 485
• MerCruiser 488
• MerCruiser 3.7L
• MerCruiser 3.7LX
• Selected MCM and MIE 3.7L applications
• Power Range: Approximately 165HP - 190HP
• Engine Type: MerCruiser 3.7L inline four-cylinder petrol sterndrive / inboard
• Year Range: Approximately 1976-1989

🔌 Function

The head seals the top of the four cylinders and controls intake and exhaust flow through the valve train while containing the spark plugs and combustion chambers.

⚠️ Common Signs of Failure

• Low compression
• Burned or leaking valves
• Cracks between valve seats
• Coolant enters a combustion chamber
• Head surface is warped
• Rocker or valve-guide wear
• Damaged spark-plug threads
• Head gasket repeatedly fails
• Valve grind or pressure testing is required before reuse

🔄 Supersession & Cross Reference

OEM Supersession Chain

• 966-9451A2 later cylinder-head assembly
• 966-6187A1 earlier related cylinder-head assembly

OEM / Related Numbers

• 966-9451A2
• 9451A2
• 9451R2 remanufactured service reference
• 966-6187A1
• 6187A1
• MerCruiser 3.7L / 224 cu in cylinder head
• 470-series cylinder-head assembly

Aftermarket / Verified Equivalents

• Complete aftermarket MerCruiser 3.7L / 470 cylinder heads
• Aftermarket valve, guide, spring and top-end gasket components
• Replacement identification: MerCruiser 470 / 3.7L cylinder head

📦 Condition

• Genuine used part
• Professional inspection and valve servicing are recommended before installation
• Removed from running engine where applicable
• In good working condition unless otherwise stated