You may have to call the dealer you bought the reverse trike from and see if they can get an OEM replacement. If not you will have to look at the aftermarket ones and find the header pipe that closely resembles yours. The muffler is not so bad to get one that will fit. But Most have to do some kind of modification to fit them on. Or you can go to a welder and have him make a 1 1/4 pipe to your fitting on the trike and then just add a muffler.
Like I had to do, On my trike the muffler was so cheap it fell apart in 3 months, so I had the muffler welded and then the pipe broke so I ordered a whole new system and that lasted the same amount of time. So I had went to a welder and had him build me a 1 1/4 header pipe from good piping then I ordered a Supertrapp Muffler and he fit the whole thing on my trike. The same exhaust system has now been on for over 4 years and it looks like new. Alleyoop
...BAD TO THE BONE..
PST150H 62mm BBK, 60mm Crank, 16/37 Tranny Gears..MOW-POWER
WATCH OUT...THOSE WHO DO NOT KNOW, DO NOT KNOW THAT THEY DO NOT KNOW