Classic/Antique Car Repair: resonator, scrap heap, resonators

Question
I have a 70 olds with a muffler and resonator, is that thing really have a purpose, is it necessary? Single exhaust, the repair manual shows it in all series 70 Olds, thanks.

Answer
Kevin, the resonator is just what the name applies, to control resonance. The resonator has no effect on the operation of the machine but is there to control exhaust noises at certain engine RPM's and load. If the car is restored original then replace the resonator, but over  the years there have e been many a resonators thrown in the scrap heap.
Brad