If you want to keep the weber carb you have now, you just cut the header flange in two parts and use that one in conjunction with the new exhaust manifold.
I'll be using Valerio's twin DCNF 40 intake manifold and I will be building my own custom exhaust manifold build to my engine (length, dia, etc).
I have been toying with the idea to draw up a twin DCOE 40/45 manifold for the wedge engine in a 3D CAD program. It could then be either 3D printed (but it has several downsides) or used to get them cast in aluminium. But to make these I would need some people to want them before I can arrange manufacturing.
On the 3D printing, this has quite a few upsides, they are made one by one, on the continent of the seller (postage is lower) by very accurate 3D printers and you can buy them straight from the manufacturer.
But the material options are a bit lower (due to the heat resistance requirements). Either alumide, but this is a gamble as its only stable up to 130°C. But stainless steel is an option to print them, stable to 900°C and very high resolution printing (even the threaded parts). But the cost would probably be too high per manifold so that making a production run to have them cast would be cheaper.
I have one week of exams left at Uni, afterwards I'll draw up a model of the manifold to see if this project is feasible.
On the side of the exhaust coating,
http://www.zircotec.com/ is definitely the best in the business. But it comes at a price too, it won't be cheap. If you have a stainless exhaust you can use heat wrap, it works almost as good at a much lower price But don't ever use it on a steel manifold, it will rust out before you know it.
Kind regards,
Serge
http://sleurs-motorsport.com/http://www.youtube.com/sleursmotorsport