The best type of muffler to use is the straight through design w/perferated holes on the inside, louvers do not flow as well.

I run a 3" straight through round type muffler w/louvers,(the muffler shop did not have the other type).This is on my 4.3 V-6.
It sounds good at idle, but it is really loud when I open it up.
Other guys w/Syclones & Typhoons run a straight through (no muffler 3" exhaust sytem) & have gotten too loud exhaust tickets.

Guys w/no mufflers say they like the idle sound ,,, but it "sounds like as$ wide open"

Some race tracks require you to run a muffler w/two or three baffles or have to be below a certain decible level.

MBHD


12 port SDS EFI