Just throwing this out there for anyone who may be fabricating a custom exhaust manifold. I've been buying my header bends from these guys for a few years now, highest quality I have been able to find. Their catalog shows high quality vee-band flange kits up to 5" dia. in stainless, and mandrel bends up to 5" dia in both stainless and mild steel.
www.spdexhaust.com (http://www.spdexhaust.com)
Just a satisfied customer.
Just put it in my favourite list. If I had known about such a supplier when I was building my engine on the Courier 96 two years ago, it would've made things easier... Same about building my hard-tail Sporty this past winter. I become a very good customer at the local machine shop.
JC
I've gotten a lot of stuff from http://www.burnsstainless.com/ (http://www.burnsstainless.com/) . They don't go into the larger sizes but for smaller stuff they are top notch. I've built several exhaust systems for bikes and polished them. They turn a pretty gold!!
Here is a manufacturer of exhaust systems! Donaldson; www.donaldsonexhaust.com (http://www.donaldsonexhaust.com)