The Muffler,exhaust, cataloged under National Stock Number 2990-00-459-7255, is classified within Federal Supply Class 2990 (Miscellaneous Engine Accessories, Nonaircraft) of the Engine Accessories group. The manufacturer of record is Merit Industries Inc. Government technical data includes 17 specifications, cited from the U.S. Government catalog. The record lists 2 manufacturer part numbers for this item, enabling identification through both NSN and commercial part number lookups. 10 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. 3 items share a part number with this NSN in the catalog (possible match — not a government interchangeability claim). Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 2990-00-459-7255 |
| Primary Part Number | 747 |
| Item Name | Muffler,exhaust |
| FSC / FSG | 2990 / 29 — Miscellaneous Engine Accessories, Nonaircraft |
| Manufacturer | Merit Industries Inc |
| Status | ACTIVE |
| Operating Position | HORIZONTAL |
| Inlet Location | LOCATED ON SIDE OF END SECTION |
| Coolant Type | AIR |
| Design Type | DRY |
| Outlet Inside Diameter | 1.880 INCHES NOMINAL FIRST OUTLET IN |
| Inlet Projection Length | 1.910 INCHES NOMINAL SINGLE INLET IN |
| Baffle Quantity | 4 |
| Muffler Design | MULTIPASS |
| Tube Quantity | 3 |
| Inlet Connection Type | UNTHREADED SINGLE INLET |
| Body Shape | OVAL |
| Surface Treatment | ZINC |
| Inlet Inside Diameter | 2.000 INCHES NOMINAL SINGLE INLET IN |
| Material | STEEL LOCATION NOT OTHERWISE SPECIFIED |
| Outlet Projection Length | 1.910 INCHES NOMINAL FIRST OUTLET IN |
| Outlet Connection Type | UNTHREADED FIRST OUTLET |
| Outlet Location | CENTRALLY LOCATED ON END SECTION |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL A — No Demilitarization Required |
| Hazard | No hazard code in the DLA record (HMIC N) |
| Criticality Code | X |
| Part Number | Manufacturer |
|---|---|
| 21446 | Walker Mfg Co (USA) |
| 747 PRIMARY | Merit Industries Inc (USA) |
| Reference | Meaning |
|---|---|
| 2534440 | 5/9 Secondary reference U.S. Government activity |
| 5702 | 5/9 Secondary reference Walker Mfg Co |
| 2534430 | 3/2 Design control — primary reference U.S. Government activity |
| 838 | 5/9 Secondary reference U.S. Government activity |
| 40W | 5/9 Secondary reference International Parts Corp Div of Midas-International Corp |
| 253440 | 5/9 Secondary reference U.S. Government activity |
| PL52 | 5/9 Secondary reference Maremont Corp |
| 1207 | 5/9 Secondary reference U.S. Government activity |
| 902 | 5/9 Secondary reference Mahle Aftermarket Inc. Dba Ae Clevite Inc |
| 2430 | 5/9 Secondary reference Harvard Industries |
NSN 2990-00-459-7255 is a Muffler,exhaust, manufactured by Merit Industries Inc, classified under FSC 2990, Miscellaneous Engine Accessories, Nonaircraft. Status: active.
NSN 2990-00-459-7255 has 2 manufacturer part numbers on file: 21446 (Walker Mfg Co), 747 (Merit Industries Inc).
3 possible matches (shared part number, not a government interchangeability claim): 6685-00-468-6866, 5330-00-545-3158, 4730-00-640-6188. Verify interchangeability with system specifications before substitution.
Key specifications for 747: Operating Position: HORIZONTAL; Overall Height: 4.000 INCHES NOMINAL IN; Inlet Location: LOCATED ON SIDE OF END SECTION; Coolant Type: AIR. 17 specifications are documented in the U.S. Government catalog.
No hazard code in the DLA record (HMIC N). Hazard information on this page is shown exactly as it appears in the DLA record.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-16.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-18.