Hi Pat
There were alot of Strap-on mufflers out there once that would fit....A new HP 61 muffler from MECOA will fit
I got a box of mufflers at the last local Club Swap/Auction for $20.00 and there was a number of odd ball mufflers that fit
just keep your eye out.
Also ask around your local model club someone will have one.
.....I would happy to swap one for a copy of a Direct Conection Ultimate Kaos Plan or Kyosho 40 Chipmunk Plan, I will even pay the postage from Australia for you
Regards
John