Exhaust› Headers, Manifolds and Components

Killer B

Holy Header 4-1 Equal-Length Exhaust Manifold

$2,445.00

SKU: KILHH4-1-SWAIN

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Special Order
Ships in 4–6 weeks
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$100 Minimum Order
30 Days Return
INSTALL DIFFICULTY
DIY PRO SHOP

Moderate — 2–4 hours

Overview

The Killer B Motorsport Holy Header is a 4-1 equal-length exhaust manifold designed to optimize exhaust flow and improve turbocharger performance. Constructed from thick-walled 321 stainless steel for durability, it features a cast 347 stainless collector for reduced turbulence and a true high-velocity merge. The header includes a V-band up pipe connection for easy installation and is SWAIN coated to reduce engine bay temperatures and protect against heat soak.
Show original supplier description
The Killer B Motorsport 4-1 Holy Header is a performance exhaust manifold engineered for Subaru EJ models, including the 2002-2014 WRX and 2004-2021 STI. Constructed from thick-walled 321 stainless steel, this header is designed for enhanced durability and resistance to extreme heat from the turbocharger. The collector is made of cast 347 stainless steel, which eliminates welds to reduce flow disruption and create a high-velocity merge. The equal-length primary design promotes quick turbo spool-up and improved performance and response across the entire RPM band. Its symmetrical primary design maintains consistent pulse velocities. The mandrel-bent smooth bends and large diameter tubing ensure non-restrictive flow, maximizing the potential of your turbocharger and reducing spool time. Additionally, the SWAIN coating applied to the header helps to reduce under-hood temperatures and protect against heat soak. Featuring a V-band up pipe connection, this header facilitates fast and leak-free installation with perfect alignment. The header weighs 17lbs and is compatible with both OEM EJ25 oil pans and the Killer B Motorsport Performance Aluminum Oil Pan. This product is proudly made in the USA. **Note:** This header may not fit some Forester, Outback, and Legacy models equipped with the OEM oil cooler.

Product descriptions are provided by our supplier partners and may not always be perfectly accurate. Not sure this fits? or call (760) 282-4645 and we’ll verify before you order.

Fitment

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Specifications

BrandKiller B
Part NumberKILHH4-1-SWAIN
CategoryExhaust
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Returns & Fitment

Built for enthusiasts. Every order is backed by our 30 day return window on eligible items. Unused and uninstalled products may be returned with approved RMA and no restocking fees when received in new condition. Orders placed through the MOTORMIA app with a complete build qualify for our Fitment Guarantee — free return shipping if the part doesn’t fit your exact setup. The guarantee covers fit only; installation must follow manufacturer instructions, and we recommend a qualified shop for parts marked Difficulty 4–5.

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Shipping

Orders are processed in 1–3 business days. In stock parts ship promptly from our partner network. Special-order items either aren’t currently stocked or are built to your spec — expect 4–6 weeks. If a part goes on backorder while your order is in the queue, we’ll reach out and work through discounted alternatives together.

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