Not very pretty welds,like J.says, it can be difficult to weld dissimilar metals, if indeed they are.Steel flanges are readily available for minimal cost if you dont want to make your own.Sorry to hear they leak,as of course it will only get worse as you put more heat and back pressure on the turbine side,JB weld? I hope he wasn't serious!Is this for the Vette?Im building an 87 firebird Turbo car now,And used weld Ells for the manifold being a log type manifold.Ill be looking for your pictures.I really like these kind of builds