Suggestions as to how to finish after the muffler
As MTNEMOMOPAR said....tail pipes with turndowns. Just like the old Mopar cop cars had.
The turndowns put most of the noise down instead of back like tips do but you can still get the rumble.
This is my dad's 68 Coronet cop car when it was about 2 weeks old. We had already shortened up the left pipe to disquise the fact that it had a large engine with duals. We told everybody it was a 383 2bbl.
Also check out this CHP car for the correct way to make the pipe.
Notice that the pipe curves up, goes straight and then turns down with a slash cut at the tip.
http://copcardotcom.fotki.com/photographs_of_dave/restorations/dave_arnolds_monaco/dsc07069.html