Mercury – Exhaust Manifold Gasket | Engine Sealing Series | Composite Marine Gasket | 8M0162487

Overview

Running a big-block MerCruiser has its own kind of music — that deep, steady rumble you feel more than you hear. But anyone who’s owned one knows that sound only stays strong when the small things are taken care of. An exhaust manifold gasket may not look impressive, but it’s one of those parts that quietly keeps everything working in harmony. Mercury Marine part 8M0162487 brings back that sense of confidence you get when the engine fires up clean, the exhaust note stays tight, and nothing leaks or ticks where it shouldn’t. It’s a simple part, sure — but you can feel the difference on every ride.

Key Features

• Designed for GM Marine big-block engines: 454 and 502 (7.4L and 8.2L V8)
• Marine-grade composite material built to withstand high heat and pressure
• Engineered to Mercury Marine OEM specifications for exact fitment
• Helps maintain proper exhaust sealing and prevents leaks or blow-by
• Durable construction resists crushing, warping, and moisture intrusion

Engine & Boat Compatibility

• Fits MerCruiser sterndrive engines based on the GM Marine big-block 454 and 502 platforms
• Compatible with 7.4L and 8.2L V8 MerCruiser engines
• Common on performance cruisers, older offshore boats, big-block sport boats, and heavy-duty sterndrive vessels
• Suitable for boats that see long idle periods, high torque loads, or significant temperature fluctuations

Performance & Practical Benefits

A big-block’s power is only as strong as its seal. When the manifold gasket is doing its job, the engine breathes the way it was meant to. You’ll hear it immediately — that smooth, full-bodied exhaust tone without the sharp ticking of a leak. The composite gasket is engineered to expand and contract with the manifold and head, holding its shape through long hours of heat, load, and vibration.

Once installed, this gasket helps maintain steady exhaust flow, improves overall engine efficiency, and prevents exhaust gases from creeping into the bilge. That’s not just about performance — it’s about safety and longevity. Big-block engines generate serious heat, and a poor seal can warp surfaces or lead to long-term damage. This OEM gasket grips evenly and stays sealed, cycle after cycle.

If you’re the kind of boater who turns your own wrenches, you’ll appreciate how cleanly this gasket sits. No crumbling edges, no awkward alignment, no guessing about whether it’ll tighten down properly. It feels solid from the moment it’s placed, and once torqued, the seal holds tight. After that first warm-up run, you’ll feel the engine settle into that deep, confident rumble you know so well.

Why Buy OEM

With exhaust components, “almost right” can become “expensive” in a hurry. Aftermarket gaskets often use generic materials that fail early or don’t match the exact thickness and density Mercury designed for these engines. An improper seal on a big-block isn’t just an inconvenience — it can lead to warped mating surfaces, power loss, or even water intrusion.

A genuine Mercury Marine gasket means a precise fit and reliable performance. It’s built for the heat, the torque, and the environment your engine lives in. Choosing OEM is the kind of practical, experienced decision boaters make when they want to avoid problems later — and keep their engines running strong season after season.

FAQ

Q1: Which engines does the 8M0162487 gasket fit?

It fits GM Marine big-block 454 and 502 engines (7.4L and 8.2L V8) used in MerCruiser sterndrives.

Q2: What makes this gasket better than aftermarket options?

It’s engineered to Mercury’s exact tolerances, with marine-grade materials that handle heat and vibration far better.

Q3: How do I know it’s the correct gasket for my setup?

Match your engine model and refer to your owner’s or service manual for part number verification.

Q4: Can it be used in both saltwater and freshwater boats?

Yes — the composite design holds up well in either environment.

Q5: Is installation straightforward for most boat owners?

Yes. With proper torque procedures, most mechanically experienced owners can install it confidently.