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stephen low 12-03-2018 04:03 AM

Header modelling kit
Any of you good folk possess or have access to a header modelling kit?

Am looking to book into a TIG welding course and my project will be to build some basic headers to connect up to my side pipes.

Ultimately I want to try fabricating my own stainless dummy side pipes.

But for now practicing on a low risk alternate exhaust option would be a good lark!

Let me know please.



Gav 12-03-2018 04:19 AM

Buy a heap of bends, cut them up and weld them together, it’s easy.
Seriously though make sure the cuts are straight, use masking tape to tape the pipes together to mock them up, then cut little holes in the tape on either side of the join to allow a tack weld.
Once you have them tacked together move on to welding them all up.

It’s a very rewarding project.

Modena 12-03-2018 11:37 PM

What Gav said. Thats how I did it.

stephen low 12-04-2018 01:18 AM

So how do you go about trying to maintain even a modicum of equal length between the individual header pipes?

Gaz64 12-04-2018 04:03 AM

Depends on what engine you are tuning for.

If you want your torque peak at 7500 and hp peak at 9500, then equal lengths become more critical, and the lengths need to calculated accordingly.

But for the most of us, if the fronts end up a little longer, and the rears end up a little shorter than a "calculated" torque peak of say 5000 rpm, the peak will be a little less, but the curve will be flatter. So some more at the bottom end, and a little more at the top.

One of my cars lost top end, when going from tri-Ys to equal 4 into 1s, both sets 1 3/4 inch primary pipe.

Here is one site I like for the construction info they have:


xb-60 12-04-2018 05:03 PM

I'm not an expert on this, so it's just my opinion here....

If we’re talking, for example, about a Ford 302W, it has a firing order of 1-5-4-2-6-3-7-8
In a Cobra application, typically we have completely separate exhausts for the right bank (cylinders numbers 1-2-3-4) and the left bank (cylinder numbers 5-6-7-8) with no X-connector between them.
So looking back at the firing order for one complete cycle, there are cylinder numbers 1-space-4-2-space-3-space-space exiting right, and numbers space-5-space-space-6-space-7-8 exiting on the left.

If we’re looking for equal length individual pipes to the collector and we have no connection between the two sides, wouldn’t that then be a pointless exercise?

If the application is a GT40 replica, then we have a proper crossover system that correctly phases the individual pulses to achieve efficient scavenging of exhaust gas.


Treeve 12-04-2018 08:53 PM

Get some of these:

Modena 12-04-2018 10:21 PM

Slowy, for me, my system goes 4-into-1-into-cat-into-1-into-4 and then into the 4" sidepipe, so the cat is under the hood, but you see 4 pipes coming out the side in traditional cobra fashion. So my "headers" are actually really short, and by result are actually pretty much the same length. You can see a picture here before they were coated

In practice, its going to make absolutely stuff all difference if you have some a couple of inches longer or shorter.

Modena 12-04-2018 10:28 PM

here's some more pics

Ozzie Goat 12-05-2018 01:50 PM

Ben, that is exhaust is amaze-balls
that answers the "how do I integrate cats" question

Bender 12-07-2018 04:21 PM

Hi Steve. I will be building my exhaust too. It will be a bit of a project. Maybe we will share some ideas. :-) For my exhaust. I don't have a mandrel to shape the tube for the square port. So I bought a set of stainless block hugger headers cheap off gumtree. It was cheaper than buying the header plates then shaping the end of the tube. I will trim the pipes off and weld the first bend on where it suits. I possibly won't need cats on mine as my car is LPG. Bender

Rob. Smith 12-08-2018 03:15 AM

Summit racing sell a "kit" of plastic pipes that clip together to make a header system. I just went the test - cut - and test way.

stephen low 12-08-2018 10:55 PM

Thanks guys.

Maybe I just start by focusing on stainless welding for a replacement set of dummy side pipes.

Given I need to have my bits with me at TAFE I can't jump between welder and car for quick checks for the headers.

The plan post course and with advice from here and the TAFE will be which TIG machine I go and buy for me to continue my welding adventures.

Wasn't sure how critical even length pipes to each side needed to be, but it doesn't appear that important in my level of use from the commentary and actual creation of headers you guys have made.

Plus I've just realised that with the course in March I'm not about dismantle the car around the planned Alpine run weekend.

So research on side pipe parts, where can people point me at?


Modena 12-09-2018 04:00 AM

this mob have every single bit and bod you can imagine, including several in stainless which you will seriously struggle to find locally (like 4-into-1). Be prepared to pay a lot for freight.

Exhaust Components - SPD Home Page B

I got my nested 90 degree bends from SPD. The rest I got from ebay (my system is not stainless)

studebaker53 12-09-2018 06:53 AM

I built my set from scratch. A couple suggestions, bolt up the sidepipes to exactly how you want them to look then build headers. Also, with the headers, don't build the pipes so close to each other that you cant get a mig/tig between pipes to weld a good bead.

CSX 4133 12-09-2018 08:09 AM

This kit would be pricey for a individual, or single use but they work very well for exhaust design.

macloft 12-15-2018 03:46 AM

Side Pipes
Try Muzza on this site. I have some off him and they are beautiful.

sjelby 01-16-2019 06:46 PM

Have the spark plugs in and the leads handy when you start to.
My first set looked great but i couldnt change plugs. ��

eschaider 01-17-2019 02:50 AM


Originally Posted by stephen low (Post 1454723)
Any of you good folk possess or have access to a header modelling kit?

Am looking to book into a TIG welding course and my project will be to build some basic headers to connect up to my side pipes.

Ultimately I want to try fabricating my own stainless dummy side pipes.

But for now practicing on a low risk alternate exhaust option would be a good lark!

Let me know please.



Didn't see your post in Dec, Steve so this response is a bit stale.

That said, I think this is what you are looking for, click here => ICE Engine Works


HM-BUILDER 01-29-2019 09:24 AM

Modena. did you get the cats from SPD?

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