Im looking at buying a test-pipe but I need to put a extra bung in for a wideband. My question is where should the bung be and should it be any angle?

 

It needs to go on the side for sure. The best thing you can do is to put the test pipe up. Thread the bung on the sensor and mock were it fits best and can be taken out with out having to take the whole test pipe off, yet clear of hitting anything. Take a sharpie and mark it, drill it, weld it. if you have a old junkie sensor put that in the bung and weld it on with that so that the bung keeps shape.

Shoot me a PM if you need any help.