new here and can't find what im looking for
 

well hi everybody i got got my hands on a 87 na 2+2 which has a bad leak in one of the cats I've bought a track pipe which has a tube on the side which im guessing is to hook up to the 5/6 valves but what do i do with the rest of the backpressure tube which runs to the back of the engine can i just block that tube or what do i need to do thanks for any help