BORLA 40359 ProXS Universal Performance Muffler 3" Offset Inlet / 3" Center Outlet 14"
- 3 inch inlet and outlet, offset and center layout
- 14 x 4 x 9.5 inch oval body
- 19 inches overall length, unnotched necks
- T-304 stainless steel
- Reversible design
- 3.99 kg item weight
Last refreshed Oct 2, 2026 · Based on the Amazon listing and published specifications, not hands-on testing.
A universal oval stainless muffler with unnotched necks. The title and description disagree about the offset side, and the spec table says vehicle specific fit, so check the layout against your pipes.
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ASIN: B000Q7MBTKModel: 40359Category: Mufflers
Overview
Fitting an oval stainless muffler into a truck exhaust run is the use here, with a Borla ProXS body that is reversible. The necks are left unnotched, so the builder trims or adapts them for the application.
Borla builds the ProXS from stainless steel for long service life, and the reversible body gives some freedom in how it is turned. The listing swaps the offset between inlet and outlet, and the fit type conflicts with the universal configuration.
Who it's for
A fabricator working on a truck exhaust with matching pipe size can place the oval body and trim the necks as needed. Anyone who needs a direct fit for one named vehicle, or who cannot tell which port is offset, should confirm with Borla.
Pros and cons
- T-304 stainless construction
- Unnotched necks for custom work
- Oval body shape
- Offset port conflicts between title and description
- Fit type conflicts with universal
- No vehicle named
- Clamps and hangers not listed
Performance notes
The oval stainless body sets how much room it needs under the vehicle, and the offset port changes how the pipes line up. The listing gives no sound level or flow data, so tone is not described here.
Where it stands among mufflers
- #10 most-searched brand and model of the 15 mufflers lines we track (by search demand, not sales).
From the specs of the 15 mufflers we list; not a test result.
Specifications
| Model | 40359 |
|---|---|
| Dimensions & fit | |
| Inlet size | 3 inches |
| Overall length | 19 inches |
| Item dimensions | 14 x 4 x 9.5 inches oval |
| Weight | 3.99 kg |
| Construction & materials | |
| Material | T-304 Stainless Steel |
| Compatibility & installation | |
| Vehicle type | Truck |
| Other details | |
| Configuration | Universal, offset and center |
| Fit type | Vehicle Specific Fit |
| Shape | Oval |
Frequently asked questions
Will the Borla 40359 muffler fit my truck?
The configuration says universal and the vehicle type says truck, but the fit type row says vehicle specific. No vehicle is named, so check pipe size and layout.
Which port is offset on the Borla 40359?
The title says offset inlet and center outlet, while the description says center inlet and offset outlet. Ask Borla which is correct.
What does unnotched mean for the Borla 40359?
The description lists unnotched necks, so the pipe ends carry no cut-outs and can be trimmed to suit.