Timing Cover Gasket – Fits Mercury/Mercruiser Big Block V8 (454/502) (Replaces Mercury 27-54529)
Timing Cover Gasket – Fits Mercury/Mercruiser Big Block V8 (454/502) (Replaces Mercury 27-54529) is backordered and will ship as soon as it is back in stock.
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Worry-free returns
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Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Timing Cover Gasket – Fits Mercury/Mercruiser Big Block V8 (454/502...
Product Details
This high-quality aftermarket Timing Cover Gasket is designed for a precise fit on Mercury/Mercruiser Big Block V8 (454/502) engines manufactured across various models from 1969 to 2001. It ensures a reliable seal to prevent coolant and oil leaks from the front of the engine.
It serves as a direct cross-reference for Mercury part 27-54529 and Hardin Marine 700-30440.
- Engineered for direct OEM-style replacement and fit.
- Constructed from durable paper/composite gasket material.
- Sold as a single, individual gasket.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket suppliers.
| Brand | Part Number |
|---|---|
| Mercury | 27-54529 |
| Hardin Marine | 700-30440 |
Engine & Model Compatibility
Confirm your engine model and year in the table below.
This part fits a wide range of Mercury and Mercruiser big block engines. Please verify your specific model and serial number range before ordering.
| Brand | Model | Rated HP | Engine | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Mercury/Mercruiser | 325 | 325 | GM 427 V-8 | 1969–1972 | 27-54529 | Serial Range: 2278747-3780449 |
| Mercury/Mercruiser | 325 MIE | 325 | GM 427 V-8 | 1968–1974 | 27-54529 | Serial Range: 2278747-3780449 |
| Mercury/Mercruiser | 330 | 330 | GM 454 V-8 | 1977–1981 | 27-54529 | Serial Range: 4623115-6083144 |
| Mercury/Mercruiser | 330 | 330 | GM 454 V-8 | 1982–1987 | 27-54529 | Serial Range: 6083145-0B816540 |
| Mercury/Mercruiser | 330 MIE | 330 | GM 454 V-8 | 1977–1980 | 27-54529 | Serial Range: 4623115-5889913 |
| Mercury/Mercruiser | 340 MIE W/B/W | 340 | GM 454 V-8 | 1981–1987 | 27-54529 | Serial Range: 5889914-0B788365 |
| Mercury/Mercruiser | 350 MIE | 350 | GM 454 V-8 | 1974–1976 | 27-54529 | Serial Range: 3780450-4623109 |
| Mercury/Mercruiser | 370 TRS | 370 | GM 454 V-8 | 1978–1985 | 27-54529 | Serial Range: 4179554-6721527 |
| Mercury/Mercruiser | 370 TRS | 370 | GM 454 V-8 | 1985–1987 | 27-54529 | Serial Range: 6721528-0B714586 |
| Mercury/Mercruiser | 390 | 390 | GM 482 V-8 | 1969–1970 | 27-54529 | Serial Range: 2781129-2825059 |
| Mercury/Mercruiser | 390 MIE | 390 | GM 482 V-8 | 1969–1970 | 27-54529 | Serial Range: 2781129-2825059 |
| Mercury/Mercruiser | 400 TRS | 400 | GM 454 V-8 | 1980–1986 | 27-54529 | Serial Range: 4179554-0B457644 |
| Mercury/Mercruiser | 420 | 420 | GM 454 V-8 | 1987–1989 | 27-54529 | Serial Range: 0A398941-0B622418 |
| Mercury/Mercruiser | 425 (GEN. V) | 425 | GM 454 V-8 | 1992–1993 | 27-54529 | Serial Range: 0A398941-0D937011 |
| Mercury/Mercruiser | 425 | 425 | GM 454 V-8 | 1990–1992 | 27-54529 | Serial Range: 0A398941-0D937011 |
| Mercury/Mercruiser | 440 TRS | 440 | GM 454 V-8 | 1983–1986 | 27-54529 | Serial Range: 4179554-0B485220 |
| Mercury/Mercruiser | 454 MAG ALPHA | 454 | GM 454 V-8 | 1986–1988 | 27-54529 | Serial Range: 0A631894-0B785148 |
| Mercury/Mercruiser | 454 MAG BRAVO | 454 | GM 454 V-8 | 1988–1992 | 27-54529 | Serial Range: 0B721206-0D805068 |
| Mercury/Mercruiser | 460 TRS | 460 | GM 482 V-8 | 1983–1986 | 27-54529 | Serial Range: 4179554-6181046 |
| Mercury/Mercruiser | 465 (GEN. V) | 465 | GM 502 V-8 | 1992–1994 | 27-54529 | Serial Range: 0C849992-0F213244 |
| Mercury/Mercruiser | 465 | 465 | GM 502 V-8 | 1990–1992 | 27-54529 | Serial Range: 0C849992-0F213244 |
| Mercury/Mercruiser | 500 Bulldog | 500 | GM 540 V-8 | 1990–1996 | 27-54529 | Serial Range: 0C577254-0F745405 |
| Mercury/Mercruiser | 500 Bulldog | 500 | GM 540 V-8 | 1999–2001 | 27-54529 | Serial Range: 0L414620-0M050281 |
| Mercury/Mercruiser | 502 MAG BRAVO | 502 | GM 502 V-8 | 1990–1992 | 27-54529 | Serial Range: 0C878221-0D824588 |
| Mercury/Mercruiser | 525 SC | 525 | GM 454 V-8 | 1991–1992 | 27-54529 | Serial Range: 0D456000-0F348963 |
| Mercury/Mercruiser | 525 SC (GEN. V) | 525 | GM 454 V-8 | 1992–1995 | 27-54529 | Serial Range: 0D456000-0F348963 |
| Mercury/Mercruiser | 575 | 575 | GM 540 V-8 | 1986–1992 | 27-54529 | Serial Range: 0A677429-0D763716 |
| Mercury/Mercruiser | 600 SC | 600 | GM 502 V-8 | 1991–1996 | 27-54529 | Serial Range: 0D456489-0F877642 |
| Mercury/Mercruiser | 7.4L BRAVO | 7.4L | GM 454 V-8 | 1988–1991 | 27-54529 | Serial Range: 0B771113-0D603117 |
| Mercury/Mercruiser | 7.4L MIE W/B/W | 7.4L | GM 454 V-8 | 1988–1992 | 27-54529 | Serial Range: 0B788366-0D715493 |
| Mercury/Mercruiser | 7.4L MIE W/HURTH | 7.4L | GM 454 V-8 | 1989–1992 | 27-54529 | Serial Range: 0C391564-0D715493 |
| Mercury/Mercruiser | 8.2L MIE W/HURTH | 8.2L | GM 502 V-8 | 1990–1992 | 27-54529 | Serial Range: 0C878221-0D857199 |
| Mercury/Mercruiser | 800 SC (GEN. V) | 800 | GM 572 V-8 | 1993–1998 | 27-54529 | Serial Range: 0D763836 and up |
Technical Specs
- Product Type
- Timing Cover Gasket
- Installation
- Direct OEM replacement
- Material
- Paper/Composite
- Dimensions
- 13.0" L × 10.0" W × 1.13" H
- Weight
- 0.023 kg (0.05 lb)
- Warranty
- Covered by a standard manufacturer warranty when purchased from an authorized dealer.
What’s in the Box
- 1 x Timing Cover Gasket (Replaces OEM #27-54529)
Installation Notes
- Disconnect the negative battery terminal for safety.
- Drain the engine coolant into a suitable container.
- Remove any serpentine belts, pulleys, and accessories that block access to the timing cover.
- Remove the crankshaft pulley/harmonic balancer using an appropriate puller tool.
- Carefully unbolt and remove the old timing cover. Note the location of different bolt lengths.
- Thoroughly clean all old gasket material and sealant from both the engine block and the timing cover mating surfaces.
- Align the new gasket on the timing cover. Apply sealant only if recommended by your engine's service manual.
- Reinstall the timing cover and tighten the bolts in the correct sequence to the manufacturer-specified torque.
- Reinstall the harmonic balancer, pulleys, and belts.
- Refill the cooling system with the correct type and amount of coolant.
- Reconnect the battery, start the engine, and carefully inspect for any oil or coolant leaks.
Troubleshooting & FAQ
How do I know if this gasket will fit my specific engine?
Verify your engine model, year, and serial number against the compatibility chart on this page. This gasket is a direct replacement for OEM part 27-54529, which is the most reliable way to confirm fitment for your Mercruiser Big Block V8 engine.
What are common signs of a failed timing cover gasket?
The most common symptoms are visible oil or coolant leaks from the front of the engine, around the edges of the timing cover. This can lead to engine overheating (if coolant is lost) or low oil pressure. You may also find coolant mixed in your engine oil, giving it a milky appearance.
Is any sealant required with this gasket?
While this gasket is designed to seal effectively on its own, some mechanics apply a thin bead of RTV silicone sealant at critical points, such as where the oil pan and block meet the cover. Always consult your engine’s official service manual for the recommended procedure for your model.
Is this an OEM part?
This listing is an aftermarket replacement (not OEM). It's built to OEM-level specifications with comparable materials. All parts are manufactured in an ISO 9002 facility and are batch-inspected for quality and consistency.
How fast is shipping?
We ship worldwide quickly—typical transit is 5–15 days. Standard shipping is free for most regions. Expedited options, where available, will appear at checkout.
What is the warranty and return policy?
This part is covered by a 1-year warranty against manufacturing defects under normal use. If you encounter an issue, please contact our support team with your order details. Returns are accepted within our standard window, provided the part is unused and in its original packaging. See our full policy page or reach out for instructions.
Safety & Important Info
- Verify images and specifications against your original part before purchase. If anything differs—even if your model appears on the compatibility list—do not purchase.
- This is an aftermarket replacement part, not an original equipment manufacturer (OEM) component.
- Professional installation is highly recommended for safety, performance, and to prevent engine damage.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and rigorously tested for real-world conditions.
- Fast Global Fulfillment — We offer free standard delivery to most regions, with typical transit times of 5–15 days.
- Manufacturer-Direct Value — By working directly with manufacturers, we provide fair pricing without compromising on materials or quality control.
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