Steve Beckman,

I have redrawn my manifold bracket to accept the flanged type header
tube. The four holes are to accept the top clamp plate. I have made the
plate a little bigger to accommodate this - now if I can only work out
the best way to do the flanges, but I'm working on it.
George ( down under)

Steve Paul and all,
OK, one phone call got me the information I needed on manufacturing the two
piece exhaust flanges.
It can all be easily done, it just cost a fair bit of money for the tooling
to press the flanges of the bottom and top flanges and possibly the stub
tube as well.
The blanks can be cut using traditional laser, water-jet etc.
The blanks are then pressed to produce the flanges in the bracket.
I estimated 6mm bottom flange and a 4mm top flange.
The cost of this pressing is quite reasonable, a few dollars a set.
SS is not a problem - just requiring larger press.
The biggest cost is the press tooling which is quite high, perhaps $3,000
and we would require two sizes as the top will be about 3mm bigger than the
bottom. So we are to $6,000 and we would need to press a stub tube to get
accurate surface mating. A Neat $10,000 should do it unless someone has some
contacts in China that could do it for a quarter of the cost.
Anyone got the spare cash to take up the challenge. I figure at $100 a set
of two you would get your money back from the sale of 500 sets- then you
might make a profit of about $20 a set.
Can anyone get a price from Powersport?
George ( down under)

Some of that stuff can be bought off the shelf from McMaster Carr.