Sierra Head Gasket 18-3879 - Replaces 3853732 - Fits Ford 302 (5.0L) 351 (5.8L) CID Marine Engines

The Sierra 18-3879 Head Gasket is a marine engine head gasket engineered to seal the mating surface between the cylinder head and engine block on Ford 302 (5.0L) and 351 (5.8L) CID marine engines. It is built to meet or exceed original equipment quality, giving it a reliable seal against combustion pressure, coolant, and oil at the head-to-block joint. A properly fitted head gasket is critical to engine performance: it prevents coolant from entering the cylinders, stops combustion gases from escaping into the cooling system, and maintains compression across all cylinders. The Sierra 18-3879 is a direct cross-reference for OEM part number 3853732, making it a straightforward replacement when servicing or rebuilding a compatible Ford marine powerhead. Whether you are performing a routine head gasket replacement after overheating, addressing a blown gasket, or completing a full engine rebuild, this gasket is sized and specified to match the original fitment for Ford 302 (5.0L) and 351 (5.8L) CID engines. Sierra manufactures marine parts to work reliably in the demanding marine environment, and this head gasket is designed as a like-for-like replacement for the original equipment part it supersedes.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-3879
• Product Type: Head Gasket
• Engine Fitment: Ford 302 (5.0L) / 351 (5.8L) CID Engines
• Replaces (OEM): 3853732
• Weight: 0.34 pounds
• UPC: 030999563132

Fitment

• Ford 302 (5.0L) CID Engines
• Ford 351 (5.8L) CID Engines

Replaces (OEM)

• 3853732

Frequently Asked Questions

What engines does the Sierra 18-3879 head gasket fit? It fits Ford 302 (5.0L) and Ford 351 (5.8L) CID marine engines.

What OEM part number does the 18-3879 head gasket replace? It replaces OEM number 3853732, making the Sierra 18-3879 a direct cross-reference for that part.

Is the Sierra 18-3879 head gasket made to OEM specifications? Yes, the Sierra 18-3879 Head Gasket is built to meet or exceed original equipment quality.

How much does the 18-3879 head gasket weigh? The Sierra 18-3879 Head Gasket weighs 0.34 pounds.

Will this gasket work on a Ford 351 Windsor marine engine block? The Sierra 18-3879 is specified for Ford 302 (5.0L) and 351 (5.8L) CID engine displacements; confirm your engine's CID rating matches before ordering.

What is included when I order part number 18-3879? You receive one Sierra 18-3879 Head Gasket sized for the head-to-block joint on the applicable Ford 302 (5.0L) / 351 (5.8L) CID engine.

Why does a marine engine need a head gasket replacement? A head gasket like the 18-3879 seals the cylinder head to the engine block; it is typically replaced after overheating, a blown gasket, or during an engine rebuild to restore proper compression and prevent coolant intrusion.

Is the 18-3879 an aftermarket or genuine Sierra part? It is a genuine Sierra part, manufactured to meet or exceed the quality of the original equipment gasket it replaces (OEM 3853732).

Can I use the UPC to verify I am ordering the correct gasket? Yes, the Sierra 18-3879 Head Gasket carries UPC 030999563132, which can be used to confirm the exact part at checkout.

Does the 18-3879 fit both the 302 and 351 Ford CID engines with the same part number? Yes, the same Sierra 18-3879 part number covers both the Ford 302 (5.0L) and 351 (5.8L) CID engine applications.