Answer JMB makes two types of cans -one is muffled ONLY and very numb to length -easy to setup and quiet .
The other is a tuned setup and requires longer header .
I can only find one type of in-fuselage silencer on the JMB site.
Designated e.g. M 60/60/270 or M 80/70/300.
Which type is this?
Magne