Need Advice on Exhaust

Hey guys, Ive got a '71 dodge demon and it has a 225 slant six in it but it sounds like a pussy car. What would I need to do to get it to sound more like a muscle car? This is my first car project and I need all the help I can get. Thanks guys!

This is an option.

[ame="http://www.youtube.com/watch?v=b9XAC-BvUyo&feature=player_embedded"]Shonky and the SoundRacer V8 - YouTube[/ame]