PartsTable TECHNICAL DATA SHEET
JULY 2026Technical Data Sheet

8656 ITEM 6Seat,valve

William E Williams Valve Corp · NSN 4820-01-351-2978 · FSC 4820 · No Item Name Available
Verified by PartsTable
NSN 4820-01-351-2978 — this item is cataloged by the U.S. Government under National Stock Number 4820-01-351-2978. Primary manufacturer part number: 8656 ITEM 6.
Features
  • Seat,valve — FSC 4820
  • Style Designator: PLAIN
  • Material: STEEL BODY
  • 2 verified cross-references
  • Primary manufacturer: William E Williams Valve Corp
Applications
  • Flow control in piping systems
  • Pressure regulation
  • Steam and fluid isolation
  • Applications requiring Steel Body construction
General Description

The Seat,valve, cataloged under National Stock Number 4820-01-351-2978, is classified within Federal Supply Class 4820 (No Item Name Available) of the Valves group. The primary manufacturer of record is William E Williams Valve Corp. Government technical data includes 2 verified specifications, sourced from the Federal Logistics Information System (FLIS). This item has 2 commercial cross-references from 1 manufacturer, enabling identification through both NSN and commercial part number lookups. 10 verified substitutes exist in the FLIS interchangeability database. Current acquisition status: Active.

Technical Specifications
ParameterValue
NSN4820-01-351-2978
Primary Part Number8656 ITEM 6
Item NameSeat,valve
FSC / FSG4820 / 48 — No Item Name Available
ManufacturerWilliam E Williams Valve Corp
StatusACTIVE
Style DesignatorPLAIN
MaterialSTEEL BODY
Lifecycle & Compliance
Acquisition StatusACTIVE
HAZMATNo
Verified Substitutes 10
2990-00-192-9203T-8656 INTERCHANGEABLE
Muffler,exhaust
Cummins Filtration Inc.
5930-00-259-834124629 INTERCHANGEABLE
Switch,toggle
Naval Ship Systems Command
5360-00-359-8645 INTERCHANGEABLE
Spring,tension
2010-00-499-24778656 INTERCHANGEABLE
Plate,floating
Twin Disc, Incorporated Dba Twin Disc Mid-Atlantic
5950-00-864-4663617226-9 INTERCHANGEABLE
Transformer,power Autotransforme
Lockheed Martin Corp
5950-01-020-652210548787 INTERCHANGEABLE
Reactor
Combat Capabilities Development Command (ccdc) Armaments Center Dba Ccdc Div Logistics Research and Engineering Directorate
2010-01-141-3488 INTERCHANGEABLE
Propeller,marine
7510-01-315-86568656 INTERCHANGEABLE
Tab,signal
Safina Office Products, Inc. Dba Safina Office Products Inc
1680-01-449-28708656 INTERCHANGEABLE
Actuator,electro-Mechanical,line
Cef Industries, Llc Dba Cef Industries Inc
1680-01-475-58538656 INTERCHANGEABLE
Actuator,electro-Mechanical,line
Lockheed Martin Aeronautical Systems Support Company Dba Lmassc
Cross-Reference Index
Part NumberManufacturer
8656 William E Williams Valve Corp (USA)
8656 ITEM 6 PRIMARY William E Williams Valve Corp (USA)
Related Parts
2990-00-192-9203INTERCHANGEABLE
MUFFLER,EXHAUST
T-8656
5930-00-259-8341INTERCHANGEABLE
SWITCH,TOGGLE
24629
5360-00-359-8645INTERCHANGEABLE
SPRING,TENSION
2010-00-499-2477INTERCHANGEABLE
PLATE,FLOATING
8656
5950-00-864-4663INTERCHANGEABLE
TRANSFORMER,POWER AUTOTRANSFORME
617226-9
5950-01-020-6522INTERCHANGEABLE
REACTOR
10548787
2010-01-141-3488INTERCHANGEABLE
PROPELLER,MARINE
7510-01-315-8656INTERCHANGEABLE
TAB,SIGNAL
8656
1680-01-449-2870INTERCHANGEABLE
ACTUATOR,ELECTRO-MECHANICAL,LINE
8656
1680-01-475-5853INTERCHANGEABLE
ACTUATOR,ELECTRO-MECHANICAL,LINE
8656

Frequently Asked Questions

What is NSN 4820-01-351-2978?

NSN 4820-01-351-2978 is a Seat,valve, manufactured by William E Williams Valve Corp, classified under FSC 4820 (No Item Name Available). Status: active.

What are the part numbers for NSN 4820-01-351-2978?

NSN 4820-01-351-2978 has 2 cross-referenced part numbers: 8656 (William E Williams Valve Corp), 8656 ITEM 6 (William E Williams Valve Corp).

What NSN replaces 4820-01-351-2978?

There are 10 known substitutes for 4820-01-351-2978: 2990-00-192-9203, 5930-00-259-8341, 5360-00-359-8645 and 7 more. Verify interchangeability with system specifications before substitution.

What are the specifications of 8656 ITEM 6?

Key specifications for 8656 ITEM 6: Style Designator: PLAIN; Material: STEEL BODY. 2 total characteristics are documented in the Federal Logistics Information System.

Validated with multiple authoritative sources, including Government, OEM, and Certified sources.
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