Tony, I put these on about 6 yrs .ago and purchased them thru a local repair shop.At the time I think there were two mufflers available, loud,and louder. I believe the Super 40s are a little newer muffler.My mufflers are not real loud,but they have a nice rumble to them.I think that with any set of headers,or the rams horn manifolds,just about any muffler would work out real nice. Glass packs,or any performance muffler.However with glasspacks you will get a more raspier sound.Another muffler I have used is the Magnaflow muffler,sounds more like a glasspack.As far as the crossover is concerned ,I have never used one,so I cannot comment on them.My 55 has just the right rumble to it. Everybody thinks it has a big block in it when I pull into a cruisin,but its just a little old 350.I am fortunate to have two good speed shops in my area,where I can always get good reccomendations on parts.I have heard some of the guys running the Flowmaster Super 40s and to me they are a little too loud,they sound just like straight pipes.But then again thats just personal prefference.
