Short straight pipes are the loudest, but it's mostly noise and no tone.
Original 50s Smithy's had metal shavings for packing.
The new repros have glass fiber that doesn't burn or melt, like 60s glasspacks did.
Forget any of the new glasspacks - they just sound like plastic toys.
Brockman Mellowtone steelpack mufflers give the closest to open pipe sound without the noise.
I run 17" shorter ones on my daily 235, exiting just before the rear wheels with turn downs.
On my current coupe/261 project I will use the same length muffler and also add cut-outs behind the front wheels.
The 12" version is used for muffler rapping contest, as it's the loudest you can get with a 'muffler'.
