hi, the new(er) motor won't come with one (if it does i would be extremely surprised) just leave it where it is and plumb into it with the new motor. you should keep it (choice is yours) and do you live where they run for emissions?. Your car might not pass if you don't have it hooked up. the post i linked to explains what it does and how it works on cars. (yes it was a newer link to toyotas, however, same principals at work.)
cheers