RE: Muffler for Gold Head .60
The O.S. 744 A muffler fits the Gold Head 60. It's a bolt throughthe muffler type. There is another 744 muffler but it's the "B" (744B) that fits the O.S. .61 SF which is a bolt through the engine case muffler.
The 744A also fits the .61 FSR. The O.S. Max .61 FSR on has the letters SR on the right side of the engine in a circle.
The 744A is a common muffler and usually easy to find. It's a better muffler than one that uses a strap around the cylinder.
Frank