27-863726 4" Wet-Joint Exhaust Bellows Kit for MerCruiser 454/502

Wet-Joint Manifold Exhaust Hose Bellows Repair Kit for MerCruiser 454 / 502 CID Big-Block V8

This wet-joint manifold exhaust hose bellows repair kit is intended for servicing the exhaust hose-bellows connection on specified MerCruiser Stern / Out Drive Model 330–370 big-block V8 engines (GM 454 / 502 CID, 1981 & up) with a 4-inch wet-joint exhaust configuration. Primary MerCruiser OEM references include 27-863726 and 27-860233.

Configuration & Specifications

Engine Applications

This kit applies to the MerCruiser Stern / Out Drive application below when equipped with the specified wet-joint, 4-inch exhaust configuration. Confirm your Model 330–370 designation, GM 454 or 502 CID displacement, wet-joint exhaust design, required gasket version, and cooling configuration before ordering.

• MerCruiser Stern / Out Drive Model 330-370 — V8 Big Block (B.B.), GM 454 / 502 CID. Years: 1981 & up. Exhaust configuration: Wet-Joint Model, 4" designation. Fits when specified (Wet-Joint, 4" model; match required gasket version and cooling configuration)

Reference Numbers

The numbers below are provided for part identification and cross-reference only. They do not establish manufacturer identity or guarantee direct interchangeability across every individual component or gasket configuration.

Supplied Parts

• Wet-Joint Manifold Exhaust Hose Bellows Repair Kit

Service & Installation Notes

General service guidance only. Use the service manual for your exact engine and exhaust configuration.

1. Allow the engine and exhaust system to cool completely, shut off the battery switch or disconnect the battery, and take precautions to prevent accidental starting before servicing exhaust components.
2. Drain the relevant wet-joint exhaust passages in accordance with the MerCruiser service manual before loosening hose clamps or removing the exhaust hose bellows.
3. Support heavy exhaust elbows or risers as required, and protect mating flange surfaces and hose sealing areas from gouges, corrosion scale, or old gasket debris during disassembly.
4. Compare the replacement parts, hose connection diameter, and any gasket flow passages against the original wet-joint configuration and cooling system setup before reassembly.
5. After installation, run the engine only with a verified cooling water supply and inspect the exhaust hose-bellows connection for water or exhaust leaks. Shut the engine down immediately and inspect if any leakage or abnormal temperature occurs.

The Serdamarine Approach

Exhaust parts need a configuration match. Serdamarine focuses on marine exhaust manifolds and their related service parts. Application details, connection requirements and public reference numbers are presented together to support part selection.

Questions Before Replacement