Description 4931256 HD is a heavy-duty aftermarket exhaust manifold engineered for Cummins QSM11 marine engines running a wet exhaust. It replaces OEM part 4931256 and supersedes 3973334, offering enhanced corrosion resistance and precise machining to withstand high-temperature saltwater exhaust cycles. Call FS Equipment to verify against engine serial number (ESN) and control parts list (CPL). Supersession Chain: 3973334 → 4931256 → 4931256 HD Applications: Cummins QSM11 marine engines Related Parts (confirm by ESN/CPL): 3955339 — Exhaust manifold gasket (ports 1 & 6) — qty 2 3328948 — Exhaust manifold gasket (ports 2–5) — qty 4 4965698 — Exhaust manifold cap screw — qty 12 3037536 — Threaded plug (sensor/blank-off) — qty 1–3 3037537 — O-ring seal for threaded plug — qty 1–3 3040813 — Alternate threaded plug — qty 1