360 la headers & straight pipe

Your low PO 360 from truck van won't be that cool with no muffs
Be loud but not like a HP with compression and cam.
And the needs muffs for backpressure was covered on Engine Masters.
Headers with extensions was best. The formula was, painted a pipe and someplace at 16 to18 or 19 inches the paint burned off. That's where to end the pipe coming off the collectors
I think I would grab a bolt on from Summit set up if on the cheap. Or Pypes , or Flowmaster of ya like drone for street use.
In my humble opinion, after over 30 years of playing, it seems to me that you Need BP, to have any bottom end on a street car