JC Whitney is a good cheap source. Another is to have a muffler shop bend them for you. Take your old system off and take it to them to copy. I went with a cheap $12 glass pack muffler. It sounds great and lasts for years.
Bob Shaw

87 Raizer, 4.3V6, Mod TH700R4,231CHD, detroit rear and LSD front, bouncy seats, 2" lift and 32x15 BFG MT tires.