8-4-1 Headers (Video)

[Kane00]

Can't wait to see the results.

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[CharlesC]

Regarding the tri-y. There is now flanges on both sides for the secondaries. Instead of carrying the 4 secondaries all the way to the 4-1 collector, we would merge them into their own respective single pipe. It will now be an equal length 4-2-1 header.

What is the latest on timing for these to be delivered?

 

[wingnutt]

What is the latest on timing for these to be delivered?

Leap Year

apologies @TreeFiddyAre …couldn’t help it

 

[TreeFiddyAre]

Leap Year

apologies @TreeFiddyAre …couldn’t help it

I’ll reach out again and see if I can get a fresh update on this elusive setup. Last word was March–April, so maybe we’re finally about to hear some Voodoo symphony. With any luck, the wait pays off big in both tone and performance — really hoping the juice is worth the squeeze. I’ll share whatever I find out.

 

[TreeFiddyAre]

I’ll reach out again and see if I can get a fresh update on this elusive setup. Last word was March–April, so maybe we’re finally about to hear some Voodoo symphony. With any luck, the wait pays off big in both tone and performance — really hoping the juice is worth the squeeze. I’ll share whatever I find out.

Here is the response I just got :

Finally happening. Going to try to have the majority out by the middle of April.

 

[Pistol_91]

I may have missed it but where the heck do the o2 sensors go?

 

[TreeFiddyAre]

Take a look at the cross over tubes on the CAD pics, it appears he has the bungs on the little crossover tubes

 

[Pistol_91]

I see them now. I wonder how that placement will work out.

 

[TreeFiddyAre]

I see them now. I wonder how that placement will work out.

I will report back once I get my grimmey mitts on them

 

[TreeFiddyAre]

This is the latest update from Martin @ Concept 8-4-1 :

Hey Guys,

Everything is ready! (minus 5" tips, 4" tips will be included for now until the 5" are ready in June)

We have started to pack orders. It is more of a challenge than expected, it's 7 boxes per system with several components overall.

We'll charge the remainder right before shipping (unless specified to charge early or give an advanced notice).

I'll be working on sending out an install companion/guide along with a total contents, so we can make sure everything is accounted for before attempting installation.

Thank you for making this possible.


Sounds like I may have my system in my possession around my birthday (APR 25), that would be a killer birthday gift .

 

[galaxy]

Uuhhhhhh…did he say 5” tips? Like, exhaust tips? Out the rear? Where da fuk are those gonna fit, lol?

 

[TreeFiddyAre]

Uuhhhhhh…did he say 5” tips? Like, exhaust tips? Out the rear? Where da fuk are those gonna fit, lol?

I have no idea.. I think that was a generic message for all the Coyote/Voodoo/Predator applications...idk 5"..??

 

[TreeFiddyAre]

My kit officially shipped out today… and yeah, I’m way more excited about this than a grown adult probably should be.

As soon as it lands, it’s going straight to a buddy’s shop — no “let me admire the boxes in the garage for a week” phase. We’re throwing it on the lift and getting right to work . From everything I’ve seen and heard so far, this setup should really wake the car up and let that Voodoo motor breathe the way it’s been begging to.

He’s got a dyno in-house as well, so if we’re not slammed for time, we’ll strap it down and grab some baseline vs. post-install numbers. I’m curious to see not just peak gains, but how it affects the mid-range and overall power curve, since that’s where these cars really live on the street.

On top of that, I’m going to put together some before-and-after sound clips — not just your typical “rev it and call it a day,” but actual dB measurements and frequency charts so you can see how the tone shifts. I want to capture whether it leans more into that high-pitched, exotic scream or adds some deeper aggression down low… ideally a mix of both without turning into a raspy mess...if she is messy I will be forced to cut into it and weld in some resonators that I bought just in case. But for 5+k it better not lol.

Goal is pretty straightforward: give you guys a real-world breakdown of what this system actually does — power delivery, acoustic profile, and overall driving dynamics.

I’m planning to capture not just peak numbers, but how the exhaust influences mid-range torque, throttle response, and the shape and feel of the power curve under my right foot. On the sound side, I’ll be looking at dB levels and frequency distribution to see how it shifts the character — whether it sharpens that high-frequency Voodoo wail or adds some usable aggression down low without turning into a raspy science experiment.

Selfishly… I’m hoping this setup transforms the car into something that sounds like a banshee being chased by a Kratos at +8,000 RPM — controlled chaos, not just noise.

In short: less “loud Mustang,” more precision instrument that just happens to sound slightly unhinged.

More to come once it lands and we get it on the car.
Stay tuned

Oh yeah — on the tuning side, I’m a little torn right now. I keep going back and forth between dialing it in N/A first or just waiting and doing it once the ESS setup goes on.

Part of it honestly comes down to the sound. If this exhaust hits the way I’m hoping, that will be the tipping point that pushes me straight into ESS + Griptec + all the supporting mods. But if it ends up being "good" as-is, I may just keep it N/A, get a proper tune, and enjoy the car in its raw form.

I know… deciding on forced induction based on how much I love the exhaust note probably isn’t the most “engineering-driven” approach. But let’s be honest — the GT350R is as much about the experience as it is the numbers. If it doesn’t make you feel something as it rushes to the top of the tach in 4th-5th gear what are we even doing here?

So yeah… we’ll call it a highly scientific decision-making process based on acoustics, emotion, and a mild lack of self-control..... I have a feeling its going to get force fed

 

[TreeFiddyAre]

THE EAGLE HAS LANDED.!!!!!

…buuuuut let’s just say she didn’t exactly stick the landing without a little drama.

First off — credit where it’s due. The fabrication work is seriously impressive. The welds are clean, consistent, and look like they were laid down by someone who actually cares (rare these days). The material thickness? Absolute unit. The tubing is nice and meaty, and the mounting brackets that bolt to the engine are borderline overkill — we’re talking damn near ½” thick. Structurally, this thing looks like it could survive a blast from a Bunker Buster.

I’ll get some pics up soon as the rest of the parts arrive…
because yes — parts are still “arriving.”

Now, onto the “character building” portion of the program:

Fitment Plot Twist

Apparently, the transmission crossmember bolts interfere with the secondaries. This was not mentioned upfront (love that for us). So now we’ve got options:

Option 1: Wait ~2 weeks for a revised high-clearance crossmember with low-profile hardware
Option 2: Channel my inner fabricator, shave some material, and run low-profile hardware he linked

As much as I enjoy turning brand new parts into custom art projects… I’ll be waiting for the updated crossmember like a civilized adult.

“Some Assembly Required” (Apparently More Than Expected)
Header gaskets? Not included.
→ After dropping $5K+, I kind of expected a complete system, not a scavenger hunt.
O2 sensors: Recommended to run F-150 sensors instead of extensions
→ Translation: add to cart
Muffler valve extensions:
→ “Will be supplied in the future”
→ Ah yes… the ever-reliable future
Heat management:
→ A couple areas clearly need heat shielding… also not included
Engine bracket hardware:
→ You’ll need to source 8x M10x1.5x35mm bolts for the supplied brackets
→ Because nothing says “complete kit” like a surprise trip to the hardware store mid-build...I might end up going gucci here and using forged Titanium from ProTi ..lets see what they say about providing me the correct stuff.
Final Thoughts (for now)

This system has serious potential — the engineering and fabrication are there, no question. But from an installation standpoint, it’s currently giving:

“90% race car, 10% IKEA instructions”

I’m not touching the install until everything is here and buttoned up. The last thing I want is to get halfway through and realize I’m one missing piece away from inventing new swear words.

More to come once everything shows up and we can actually get this thing on the car. Stay tuned — this could either turn into something legendary… or a very expensive lesson in patience I will keep everyone updated on their response on when I can expect the items required to start this

 

[galaxy]

As someone who’s stuck with you through all this, my best current comment is…hhhmmmmmmm…

Right out of the gate, I don’t like the crossmember idea.

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