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Description
XForce | LS1 V8 Headers & Metallic Cat Kit | Holden VT-VZ 1 3/4" Primaries | H2-HV13B-KITXForce LS1 V8 Header & Metallic Cat Kit 1 3 4" Primaries H2 HV13B KIT Unlock the maximum potential of your LS1 V8 with the Xforce Header and Cat Kit. Crafted from high strength 201 grade stainless steel, this kit features larger 1 3 4" primary pipes designed specifically for modified or high output Gen III engines that require superior exhaust scavenging. The 4 into 1 tuned design merges into a 3" outlet for optimal flow velocity. Included in this
XForce LS1 V8 Header & Metallic Cat Kit - 1 3/4" Primaries - H2-HV13B-KIT
Unlock the maximum potential of your LS1 V8 with the Xforce Header and Cat Kit. Crafted from high-strength 201-grade stainless steel, this kit features larger 1 3/4" primary pipes designed specifically for modified or high-output Gen III engines that require superior exhaust scavenging. The 4-into-1 tuned design merges into a 3" outlet for optimal flow velocity.
Included in this performance package are 3" metallic high-flow 100-cell catalytic converters. These "race-style" cats significantly reduce backpressure compared to standard ceramic units, allowing your V8 to breathe freely. Expect a noticeable increase in torque, horsepower, and a deeper, more aggressive exhaust note. This kit is a direct bolt-on solution when paired with an Xforce cat-back exhaust system.
What's in the Box?
- 1x Pair of 4-into-1 Headers (1 3/4" Primaries, 3" Outlets)
- 2x 3" Metallic High-Flow 100-Cell Catalytic Converters
- Installation Gaskets and Bolt Hardware
Features:
- Large 1 3/4" Primaries: Ideal for cammed or modified LS1 engines requiring increased flow.
- 3" Metallic Cats: 100-cell substrate provides maximum flow while maintaining a physical catalytic brick.
- 4-into-1 Tuned Design: Precision engineered to balance exhaust pulses and improve mid-to-high range power.
- Durable Construction: Non-polished 201-grade stainless steel for long-lasting performance.
- Broad Fitment: Suits a wide range of VT-VZ Holden and HSV RWD/AWD variants.
Important Installation Notes:
- O2 Extension Looms: Required for installation as the sensor bungs are relocated (sold separately).
- Dyno Usage: It is highly recommended to use tuning pipes in place of cats when tuning on a Dyno to avoid overheating the metallic substrate.
Specifications:
- Make: Holden / HSV
- Engine: 5.7L LS1 V8
- Header Primary Size: 1 3/4" (45mm)
- Header Outlet Size: 3" (76mm)
- Material: 201 Stainless Steel
- Cat Type: 100-cell Metallic
Important Information
- The image shown may not reflect the actual product
- Shipping times may vary depending on destination and stock availability
Vehicle Applications:
HSV Maloo (01/1994 - on), GTO (01/1994 - on), GTS (01/1994 - on), Sv300 (01/1994 - on), Senator (01/1994 - on), Clubsport (01/1994 - on), Avalanche (01/1994 - on), Coupe 4 (01/1994 - on), Grange (01/1994 - on), Holden Commodore (01/1994 - on), Calais (01/1994 - on), Crewman (01/1994 - on), One Tonner (01/1994 - on), Statesman (01/1994 - on), Monaro (01/1994 - on), Caprice (01/1994 - on), Adventra (01/1994 - on)
| Make | Model | From | To | Body | Series | Engine | Variant | Drivetrain |
|---|---|---|---|---|---|---|---|---|
| HOLDEN / HSV | ||||||||
| HOLDEN | ADVENTRA | 08/2003 | 12/2007 | Wagon | VY, VZ | LS1 5.7L | All V8 | AWD |
| HOLDEN | COMMODORE | 06/1999 | 12/2007 | Sedan/Ute/Wagon | VT-VZ | LS1 5.7L | All V8 | RWD |
| HOLDEN | MONARO | 12/2001 | 07/2006 | Coupe | V2, VZ | LS1 5.7L | All V8 | RWD |
| HOLDEN | STATESMAN / CAPRICE | 06/1999 | 07/2006 | Sedan | WH, WK, WL | LS1 5.7L | All V8 | RWD |
| HSV | CLUBSPORT / SENATOR | 07/1999 | 09/2004 | Sedan | VT, VX, VY | LS1 5.7L | i V8 | RWD |
| HSV | MALOO | 03/2001 | 09/2004 | Ute | VU, VY | LS1 5.7L | i V8 | RWD |
| HSV | GTS / GTO | 04/1995 | 09/2004 | Sedan/Coupe | VS, VT, VX, VY, V2 | LS1/HSV V8 | i V8 | RWD |
Warranty Information
| Product Type | Warranty Period |
|---|---|
| 304 & 201 Stainless Steel Exhaust Systems | 60 Months |
| Accessories | 12 Months |
| Catalytic Converters | 12 Months |
| Electronic Products (Including SmartBox) | 12 Months |
| Mild Steel & 409 Stainless Steel Exhaust Systems | 24 Months |
| Mild Steel Headers | 12 Months |
| Stainless Steel Headers | 24 Months |
| Universal 304 Stainless Steel Mufflers | 24 Months |
| Universal Mild Steel & 409 Stainless Steel Mufflers | 12 Months |
Payment & Security:
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Shipping Notes
- Free Standard Shipping on $100+ Orders to the USA.
- Except Preorder products are shipped in 48 hours.
- Delivery to the USA:
- Standard Shipping : 3-10 business days
- If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
- We offer a 30-day return/exchange service after receiving.
- Final sale items are not eligible for returns or exchanges.
- To process your return/exchange, please contact us at [email protected]
- Please click here for more details>>> Return & Exchange Policy
4.0 ★★★★★
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Product Reviews
★★★★★ 5
They’re fantastic!!!!
Size: X-Large, Color: Multicoloured E-(5-pack)
My clothing size is 16/18 and XL. Even though Amazon suggested a size XXL, I ordered my normal XL and they fit perfectly.
The fabric for this style is 92% bamboo viscose and is amazingly soft and almost silky feeling. I had ordered a different boy short in this brand but they were 80% bamboo viscose and the fabric was significantly heavier. I returned those and ordered these.
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Reviewed in the United States on April 25, 2026
★★★★★ 5
My favorite underwear
Size: Medium, Color: Multicoloured C (5-pack)
Super comfortable!! They are soft and breathable. No pinching, no shifting, and relatively invisible in skirts, pants, and loose dresses. True to size. Excellent quality, holds up well. Only thing is that the wording on the front does come off after a few washes, so you have to differentiate the front from the back of the underwear by how high the seam comes up. I almost exclusively wear this underwear now, I love it!
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Reviewed in the United States on April 30, 2026
★★★★★ 5
Incredible Comfort
Size: Large, Color: Multicoloured F (5-pack)
Amazing; I’ll be ordering more. Super soft, lightweight, smooth under clothes, incredible comfort! Best underwear! I ordered these because I’m tired of underwear lines when wearing biker shorts/leggings. Other boy shorts were too long or the bottom hem too thick and both of those issues left lines around my upper leg. THESE are *just right* - perfect length and fit. No panty lines on close fitting pants, comfortable under other pants and dresses, great with jumpsuits, and fit well under slip shorts with dresses.
NOTE: These take longer to dry, than similar clothes, in the dryer. No shrinking though.
SIZE: I ordered these in size L and they fit perfectly. A little snug when first on but they loosened up. For reference I’m 5’4” tall, about 175#, carry my weight in my hips and backside,wear size L sweats/pajamas/loose pants, size 12 jeans.
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Reviewed in the United States on September 23, 2025
★★★★★ 5
Full coverage and full comfort
Size: XX-Large, Color: Multicoloured C (5-pack)
These boyshort underwear are a dream. They’re very soft, very stretchy, and very comfortable. They do not shrink when they’re washed. They’re heavy enough to make you feel like you have something covering you for discretion, but light enough to wear under any type of fabric. I have wide hips and I’m older so I don’t have a tight perky butt anymore. Most underwear tend to either ride up on me or become very uncomfortable. These stay where you put them. And they come all the way up to your waist so that there is no panty line whatsoever. The waist line is soft and comfortably. It does not dig in. They do not ride up and drive you crazy they stay where you put them. I would recommend them to anyone young or old. I have tried so many different styles and materials to find underwear that’s actually comfortable. These are the absolute best I have tried in five years. I just threw all the rest of them out.
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Reviewed in the United States on April 8, 2026
★★★★★ 4
Bamboo is an amazing fabric
Size: Large, Color: Multicoloured I (5-pack)
Comfy and soft . I’ve never worn boy shorts before so takes adjusting to. Legs roll sliding pants up but easy to adjust and smooth before zipping up then all day comfort. When I wear skirts or shorts they are perfect for that! I use to wear bike pants under skirts that don’t have to anymore. I like that they don’t creep up like regular underwear. I’m a new fan of bamboo fabric and bought briefs in bamboo as well.
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Reviewed in the United States on May 9, 2026