Picking an Exhaust and Mufflers

I bought this to hook up to my 318 with hooker headers, ran it through some flowmaster Super 40 series. Sounds amazing!

Summit Racing® Header-Back Dual Exhaust Systems SUM-680145-NM
http://www.summitracing.com/parts/sum-680145-nm/overview/year/1973/make/plymouth/model/duster