easy as 3" 4" 5"
I just made a 5" system from parts from local ( truck )parts store.
I cut stock off about 8" from top, put 3" to 4" adapter,
4" to 5" adapter. Then used 45* angle to 46" pipe, this goes
into 10" round by 52" long muffler. On the muffler used 90* bend
to go out in front of back tire. On the 90* part I used a chrome
turn down pipe which made the tip stick past edge of truck 2".
It sounds like a real truck now. All the parts total was $276. 00
I don't think you can make this go over back axle, but I wanted mine to come out the side. Hope this helps.