Originally Posted by
buzzard bait
A K&B 61 with its stock muffler will wake the dead. That's one reason I'd like to be able to run a larger prop on it. A Bisson muffler might help too.
The 65 Sportster muffler will fit; I don't know if it would help any.
The sportster muffler is very good at quieting the noise, but on almost any other engine it will likely limit power. But I wouldn't know for sure until I tried it. The sportster engine was designed with that muffler in mind. I didn't see a big gain in rpm running a .65 without the muffler (but I did get an appreciation for hearing protection. I always wear it running engines).