I am not sure, but I think Randy is at the NATS and may not see this message for a while. You better call him any way:
www.aeroproduct.netMACs product makes a 1.5Oz C/L muffler , but you have to use an adapter. MACS adapter muffler P/N 6404 and adapter P/N 6438
http://www.macspro.com/onepiece.aspPerhaps you can drill an tap the the Adapter muffler it self to fit the Enya SS40.
The other possible solution is to use a Macs Header for Enya SS40 (P/N 2430), no need for the engine adapter, then you just have to glue a Hobbico exhaust deflector (P/N HCAP2175) at the end with JB weld. The deflector fit in perfectly. I have done that and it works quite well. Just make sure you sit the header straight up so the glue does not run to the sides or down inside. Although the JB WELD will not glue the silicone it will mold perfectly around the deflector grooves and it will seal and hold the deflector in place. It would be better if you can machine an aluminum plug for the end of the Header.
If you are not fully familiar with this engine just ask for some input and help. Some Enya SS40 comes very tight from Factory and it can take a long time to break in if you do not have the proper technique. If you try to fly a tight engine without fully break in, the engine can stop with no waring.
Martin