Mercury 8M0187371 Mercury-Mercruiser Quicksilver Longblock 5.7L V-8 91-97

Mercury-Mercruiser Quicksilver Longblock 5.7L V-8 91-97

This new Quicksilver 5.7L longblock is designed for 1991-1997 models, ensuring optimal performance and peace of mind for boaters.

• GM 5.7 Liter Non‑Gen + 350 V8
• Left‑Hand / Standard Rotation
• Replaces 1991‑1997 Sterndrive or Inboard 5.7L roller‑lifter marine engines
• 3 Year Limited Factory Warranty! No core or container deposit!
• Premium components:
• 100% brass core plugs
• High volume oil pump
• Marine valve springs resist fatigue
• Super polished crankshafts using superior material and design features
• Heavy duty head and block castings:
• Resist corrosion and cracking
• Higher loading capacity
• Ability to use solid engine mounts
• Hardened valve seat installed in the cylinder heads:
• Hardened Intake & Exhaust seat inserts
• Premium alloy seat material
• Black‑X Valve Technology:
• 21N Intake valve parent material
• 24N Exhaust valve parent material
• Plasma nitride prevents valve sticking & increases toughness
• Chrome‑Cobalt alloy seats resist corrosion from alcohol fuels
• Valve life improved 42%
• 100% Advanced SIM Testing:
• Water and oil passages pressure tested 100%
• Phased rotational testing with hot oil validates all oil passages, bearings, and assembly
• Advanced compression testing verifies cylinder sealing and valve lash integrity
• Oil flush at completion of test removes break‑in debris
• Shipped without oil to prevent spillage while in transit
• Brand: Mercury
• Product Number: 8M0187371