I've had leaking flanges on both stock and aftermarket headers. If u think about the hardness of metal it is affect by heat. Adding the contracting and expanion forces, particularly acting against the bolts.....something has to give. Either the bolts break or the flange bend or the pipe separates from a welded flange. It' a science I don' understand fully, but it's a problem. Im' curious to see a no-bend flange....its gotta b very thick and impractical to install.

 

I don't have any leaks

 

flangeless system works too.

 

I never had any leaks