I agree..250 range for a good set of hedmans or hooker for a little more maybe.
I had a 76 Daytona Charger SE 360 auto with a nice set of hookers.
first set of pipes were 2.5" straight pipe with 2 turbo muffs and 2' of tail pipe bent in a 90* dumping in front of the N50s.
one night about mid night at 110 mph a cat ran across the road, went under the front bumper and the CAT-muff-2' tail pipe all got sucked under the N50 at speed with a big bump & bang then 1 open header on the slow down. went back for my muff trash and it had cut the cat clean in two.
then with no cash outlay I had 2 thrush tin can mufflers welded to the bolt on collector and 2 small 45* x 8" long turn downs.
then it had the sound of power thrush tin cans were famous for.
IIRC trans R&R sucked with headers but well worth it.