Hi all
I had a real problem 111dB with my exhaust.
Put new pipes on after extending the muffler the entire length of the pipe.
I used steel wool instead of fibreglass. Available at bigger shops.
Wind the wool on just like electrical tape. First in one direction and then back. Wire it at two three locations to stop it ending up one end. Wrap it lightly not tight or it will not let gases into quiten.
Result 96dB. nearly there for compliance
No one looks now. Running 351 stroker to 377. Childs/Albert rods, Dart II heads, Ice ignition, big cam, Victor Jnr. etc etc.
About 445 Hp at rear wheels. The pipes did not restrict power.
Have 2 and 1/4 inside diam.
Cheers
Bernie
Bernie Knight
Mt. Gambier South Australia.