Custom exhaust shop in your area? Or, any shop with a pipe bender could make 'em up for ya, and either install them as well, or, set 'em up as slip fit.... and then you could just use clamps. (I would prefer welded though.)

 

edlebrock makes some fat nasty donuts.. I actually have a set, still in packaging, that I'm not planning on using..

maybe this will help?