Info.
http://4m.net/showthread.php?t=89495
http://4m.net/showthread.php?t=93091
http://www.flowmastermufflers.com/backpressure.html
http://www.amazon.com/Flowmaster-325108 ... B000CNHDLY
http://www.flowmastermufflers.com/40_race.html
as above but needs to be center in center out.