PartsTable TECHNICAL DATA SHEET
JULY 2026Technical Data Sheet

3866266Muffler,exhaust

General Motors Llc Dba General Motors Llc · NSN 2990-00-778-0031 · FSC 2990 · No Item Name Available
Verified by PartsTable
NSN 2990-00-778-0031 — this item is cataloged by the U.S. Government under National Stock Number 2990-00-778-0031. Primary manufacturer part number: 3866266.
Features
  • Muffler,exhaust — FSC 2990
  • Design Type: DRY
  • Muffler Design: MULTIPASS
  • Tube Quantity: 3
  • Coolant Type: AIR
  • Operating Position: HORIZONTAL
  • Outlet Inside Diameter: 1.688 INCHES NOMINAL FIRST OUTLET IN
  • Inlet Connection Type: UNTHREADED SINGLE INLET
Applications
  • Applications requiring Steel Location Not Otherwise Specified construction
General Description

The Muffler,exhaust, cataloged under National Stock Number 2990-00-778-0031, is classified within Federal Supply Class 2990 (No Item Name Available) of the Engine Accessories group. The primary manufacturer of record is General Motors Llc Dba General Motors Llc. Government technical data includes 18 verified specifications, sourced from the Federal Logistics Information System (FLIS). This item has 20 commercial cross-references from 10 manufacturers, enabling identification through both NSN and commercial part number lookups. 12 verified substitutes exist in the FLIS interchangeability database. Current acquisition status: Cancelled.

Technical Specifications
ParameterValue
NSN2990-00-778-0031
Primary Part Number3866266
Item NameMuffler,exhaust
FSC / FSG2990 / 29 — No Item Name Available
ManufacturerGeneral Motors Llc Dba General Motors Llc
StatusCANCELLED
Design TypeDRY
Muffler DesignMULTIPASS
Tube Quantity3
Coolant TypeAIR
Operating PositionHORIZONTAL
Outlet Inside Diameter1.688 INCHES NOMINAL FIRST OUTLET IN
Inlet Connection TypeUNTHREADED SINGLE INLET
Body ShapeOVAL
Inlet Outside Diameter2.125 INCHES NOMINAL SINGLE INLET IN
Inlet LocationLOCATED ON CENTER OF END SECTION
Inlet Projection Length2.000 INCHES NOMINAL SINGLE INLET IN
Surface TreatmentZINC
Inlet Inside Diameter2.000 INCHES NOMINAL SINGLE INLET IN
Outlet Outside Diameter1.812 INCHES NOMINAL FIRST OUTLET IN
Outlet Projection Length2.000 INCHES NOMINAL FIRST OUTLET IN
Outlet LocationOFFSET ON END SECTION OPPOSITE INLET
MaterialSTEEL LOCATION NOT OTHERWISE SPECIFIED
Outlet Connection TypeUNTHREADED FIRST OUTLET
Lifecycle & Compliance
Acquisition StatusCANCELLED
HAZMATNo
Verified Substitutes 12
4820-00-036-08968876M INTERCHANGEABLE
Disk,valve
Schneider Electric Systems Usa Inc
5110-00-045-6207 INTERCHANGEABLE
Blade,rasp
6625-00-063-0896 INTERCHANGEABLE
Multimeter
5905-00-072-85312324954 INTERCHANGEABLE
Resistor,variable,wire Wound,pre
Navair and Navsea Managed Original Design Activity Dwg Not Material/parts Supplier
3110-00-100-0683749 INTERCHANGEABLE
Cone and Rollers,tapered Roller
The Timken Corporation
5330-00-136-7398 INTERCHANGEABLE
Gasket
4820-00-155-50408269 INTERCHANGEABLE
Seat,valve
Westinghouse Air Brake Technologies Corp Dba Westinghouse Air Brake Technologies Corp
5930-00-201-2581121904ML INTERCHANGEABLE
Switch,rotary
Electro Switch Corp. Dba Electro Switch Corp
5977-00-247-5358 INTERCHANGEABLE
Brush,electrical Contact
5815-00-311-9286SC-D-5064 INTERCHANGEABLE
Chest
Us Army Communications & Electronics Materiel Readiness Command Logistics Engineering Dir
Cross-Reference Index
Part NumberManufacturer
3884816 General Motors Corp Chevrolet Motor Div Special Products Dept (USA)
3866266 PRIMARY General Motors Llc Dba General Motors Llc (USA)
3874660 General Motors Corp Chevrolet Motor Div Special Products Dept (USA)
749 Ap Parts Co Industrial Sales Div (USA)
3908390 General Motors Corp Chevrolet Motor Div Special Products Dept (USA)
3923366 PRIMARY General Motors Llc Dba General Motors Llc (USA)
3866266 General Motors Corp Chevrolet Motor Div Special Products Dept (USA)
3981942 General Motors Corp Chevrolet Motor Div Special Products Dept (USA)
MUB19 Mahle Aftermarket Inc. Dba Ae Clevite Inc (USA)
3923366 General Motors Corp Chevrolet Motor Div Special Products Dept (USA)
3792269 General Motors Corp Chevrolet Motor Div Special Products Dept (USA)
8269 Harvard Industries (USA)
3923366 General Motors Corp (USA)
8876M Hunter James Machine Co Inc (USA)
1123 Arvin Industries Inc (USA)
1255 Walker Mfg Co (USA)
3831583 General Motors Corp Chevrolet Motor Div Special Products Dept (USA)
3908396 General Motors Corp Chevrolet Motor Div Special Products Dept (USA)
CH53 Maremont Corp (USA)
21293 Walker Mfg Co (USA)
Related Parts
4820-00-036-0896INTERCHANGEABLE
DISK,VALVE
8876M
5110-00-045-6207INTERCHANGEABLE
BLADE,RASP
6625-00-063-0896INTERCHANGEABLE
MULTIMETER
5905-00-072-8531INTERCHANGEABLE
RESISTOR,VARIABLE,WIRE WOUND,PRE
2324954
3110-00-100-0683INTERCHANGEABLE
CONE AND ROLLERS,TAPERED ROLLER
749
5330-00-136-7398INTERCHANGEABLE
GASKET
4820-00-155-5040INTERCHANGEABLE
SEAT,VALVE
8269
5930-00-201-2581INTERCHANGEABLE
SWITCH,ROTARY
121904ML
5977-00-247-5358INTERCHANGEABLE
BRUSH,ELECTRICAL CONTACT
5815-00-311-9286INTERCHANGEABLE
CHEST
SC-D-5064
5305-00-353-9444INTERCHANGEABLE
SETSCREW
8269
3810-00-410-0109INTERCHANGEABLE
CHAIN,SPECIAL
707049

Frequently Asked Questions

What is NSN 2990-00-778-0031?

NSN 2990-00-778-0031 is a Muffler,exhaust, manufactured by General Motors Llc Dba General Motors Llc, classified under FSC 2990 (No Item Name Available). Status: cancelled.

What are the part numbers for NSN 2990-00-778-0031?

NSN 2990-00-778-0031 has 20 cross-referenced part numbers: 3884816 (General Motors Corp Chevrolet Motor Div Special Products Dept), 3866266 (General Motors Llc Dba General Motors Llc), 3874660 (General Motors Corp Chevrolet Motor Div Special Products Dept), 749 (Ap Parts Co Industrial Sales Div), 3908390 (General Motors Corp Chevrolet Motor Div Special Products Dept) and 15 more.

What NSN replaces 2990-00-778-0031?

There are 12 known substitutes for 2990-00-778-0031: 4820-00-036-0896, 5110-00-045-6207, 6625-00-063-0896 and 9 more. Verify interchangeability with system specifications before substitution.

What are the specifications of 3866266?

Key specifications for 3866266: Design Type: DRY; Muffler Design: MULTIPASS; Tube Quantity: 3; Coolant Type: AIR. 21 total characteristics are documented in the Federal Logistics Information System.

Is NSN 2990-00-778-0031 still in active supply?

NSN 2990-00-778-0031 is currently cancelled. Check with the Defense Logistics Agency for current availability and authorized substitutes.

Validated with multiple authoritative sources, including Government, OEM, and Certified sources.
PartsTable Design LLC · partstable.com