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STM Evo 6/7/8/9 Water Neck for Radiator Cap Relocation Currently Unavailable

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The STM Custom Water Necks feature a welded top spout for the radiator cap and are designed for race applications where the radiator may be relocated or modified. This is needed to run the STM Billet Aluminum Radiator without the cap on the radiator. The STM Water Necks are available for Evo 6/7/8 and Evo 9 models and are offered with the factory hose outlet or with a custom -AN bung.

*Currently Unavailable*
STM is in the process of redesigning these. Stay tuned for a new billet replacement!

For these Applications:
1996-2005 Mitsubishi Lancer Evolution VI VII VIII
2006 Mitsubishi Lancer Evolution IX
(* Radiator cap is not included *)

Please Read Before Purchase:

This piece is for custom set-ups and race applications. Here's some guidelines:

1) This part absolutely does not delete or replace the radiator in anyway.

2) If you have a modified or custom radiator where the cap is not the highest point, or just doesn't have one at all like the STM Billet Radiator - this is what you need. This will put a cap at the highest point in the system to bleed out air when filling coolant.

3) This is a new OEM filler neck modified to have a radiator cap bung on it. It doesn't change the way the system operates at all.

4) If you have any questions or don't understand how any of our parts operate or install PLEASE ask before purchasing and installing.

Fitment:	Hose Outlet:	Part Number:	Notes:
Evo 6/7/8	Stock	STM-EVO8-WNCAP-STK	Discontinued
	-10AN	STM-EVO8-WNCAP-10AN	Discontinued
	-12AN	STM-EVO8-WNCAP-12AN	Discontinued
	-16AN	STM-EVO8-WNCAP-16AN	Discontinued
Evo 9	Stock	STM-EVO9-WNCAP-STK	Discontinued
	-10AN	STM-EVO9-WNCAP-10AN	Discontinued
	-12AN	STM-EVO9-WNCAP-12AN	Discontinued
	-16AN	STM-EVO9-WNCAP-16AN	Discontinued

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Why Drivers Choose FAST of West Chester

I can't recommend this place enough. Being able to trust a shop in the performance world is big. The 2hr drive to get there, is worth knowing the job will be done right. Very happy to have found this shop, to
support my builds going forward.

Donald Wojnar
I recently had the pleasure of working with FAST of West Chester for some performance upgrades on my 2022 WRX, and the experience was nothing short of exceptional. I opted for a Borla S-Type exhaust and Cygnus Coilovers, and the team at FAST nailed the installation, fitment, and setup to a T.

Adam Cranston
The team at FAST are excellence in every way. First, I consulted with Dave on mods for my HPDE track car. He listened and advised me on the best parts & mods to achieve my goals. He was patient & gave me space to research the options presented & worked with me through several changes before we built. Second, the build execution was flawless, proper heat shielding, bracing and poly everywhere. All components worked as advertised.

Bryce Budd
This place has been my go to shop for all things Subaru. From simple service to performance parts and tuning, they have been top notch.

William Brunell
Excellent shop. They installed a Cobb Stage 2 DP and Whiteline Sway bars and end links on my 2013 WRX. The work was done right and clean. The estimate was accurate. They were very knowledgeable, friendly and gave me the straight scoop on exactly what I was getting for the money
and what I needed to get where I want to be with it. I'd recommend them
to any car enthusiast.

Devin Greco

Real Answers From Real Builders

We install and test many of the parts we sell — so you’re getting real-world answers, not guesses.

Does it come with a warranty?

Most products we carry include a manufacturer warranty. Since we work with top performance brands, warranty coverage can vary by product. If you have questions about a specific item, reach out — we’re happy to help.

Do you offer installation help or advice?

Yes — we don’t just sell parts, we install and tune them too. FAST of West Chester is a real performance shop, and we’ve worked hands-on with many of the products we carry. If you have questions about fitment, installs, or building your setup, our team can point you in the right direction.

How fast is shipping?

Many of our products ship the same day or next business day, depending on availability. We work hard to get parts out fast so you can get your build moving without delays.

What’s your return policy?

Returns for exchange or refund are accepted within 30 days of receiving your order. Items must be in new, unused condition and in original packaging. If you have any questions, our team will help make the process easy.

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