How to mock up headers?

So, after a ton of b.s. trying to get an exhaust manifold, I'm saying hell with it and making headers, which is what I really want. I have a general idea of where they should go, but does anyone know of something long, cheap and cylindrical that will hold its shape when you bend it? Thought about using bendy exhaust pipe, but that stuff's not cheap. Also considered making a scale model of my block out of clay and running pipe cleaners...My man nixed this idea. Anyone have a better idea?

 

I've built a lot of headers for various vehicles over the years, and haven't found any good reason to mock up the tubes. You really don't want to try to have them bent out of a single piece at the muffler shop. If you are using "U" bends, set up the flange and collector and build from one to the other. Keep bends to a minimum (don't put in a lot of extra bends trying to make them all exactly the same length). Also, practice welding on thin material (MIG is nearly impossible to get right) BEFORE starting the project.

 

coat hangers....welding rods....just to get it roughed out of how you want them to lay...

 

Get yourself some u bends, start at the header flange and work your way back. Cut, tack, get angry, and repeat.

Do they make headers for your motor? Modifing something that fits close might be a bit easier than making headers from scretch.

 

This is on your flat 6? Just buy them from me.

 

A good header trick if you're dealing with an engine swap is to buy headers for your engine and ask for the smallest car that engine came in.

IE: 390 FE Ford in a 68 Mustang.

Usually the right side is a bolt-in and the left side may have to have one (usually) or two pipes altered.

You may or may not want to weld a couple of two bolt flanges at the end of each altered pipe and if the header flanges are one piece, hacksaw them in two so you can remove the altered pipe easily.

 

You can also mock them up using flexible aluminum tubing (look for the accordian type) from Home Depot. Once you have the tubes in the desired location, simply fill them with the spray type foam insulation that hardens. You can then have a fairly rigid model to build from. Pretty cheap and avoids wasting bends if you aren't fabbing your own. Good luck.

 

The fabguys are right, to build headers you get 'u' bends and start at the flange and work out, one tube supports the next etcetc. Usually we know what the finished product will be like and we cut the bends to create. A hateful process. What may help you is to use shopvac hose with a piece of brazing rod taped to it at regular spacing. Bend the rod to hold the shape of the vacuum cleaner tubing, once you get satisfied with how it shoud go tell your amn to make em. Easier that way.

 

There are a lot of ways to mock them up. I guess my point was that if you are using U bends it is very time consuming and difficult to get exactly the right amount of bend and exactly the right radius every time. And then you still have to do it all over again in metal. An angle finder and straitedge and a good eye for direction usually works better and faster...

 

I found it helpful to mock my headers up just to make sure there was enough room to get the pipes through a couple of tight areas, and to get an idea of the best way to route the pipes.

The local pick-a-part had some heater vent tubing for a couple of bucks, so I used that.

If you have a lot of space to run the tubes, it probably isn't necessary.

 

All the headers that I have made we used that flexible dryer tubing that you get at the hardware store for general layout and design. You can get it in many different sizes and it works well to get the basic layout of the headers figured out. It works really well if you are building the headers all equal length for peformance. Then you know where the twists and turns need to be and translate that to your u bends.

 

Brilliant! This is what I was looking for. IF I don't buy them from Moose, this is what I will do. Not a lot of space in there, and I don't want to buy more than I need. Thanks for the tips everyone!

 

what is wrong with your stock exhaust manifold? put a "wanted" ad on craigslist for one.

 

I build header prototypes for as part of my job. The problem with the aluminum flexi tube or plastic is the radius' won't be like what you can buy and then you get the frustration of starting over again. Building nice headers is not an easy job and takes time and practice.