Ralph,

I've attached a couple of picture for you.

The smaller muffler is the original that I bought back in 1983 with my first G60. It's a so called venturi type and rather small. The outlet is 6mm dia. and the front venturi "inlet" is also 6mm dia. The effect here is that the muffler exhausts at both ends (a bit like me) and doesn't muffle much at all. With the front venturi inlet blocked off, the engine looses considerable power.

The bigger muffler has about double the internal voume and an outlet of about 9mm. It is the muffler originally supplied with the first true 60 size schneurle ST, the S60 with the dished head. It is a good useable muffler.

The finned header was also sold with pipe as an extra to fit the S60 and is the combination I mostly use on my G60's.

Bear in mind that the the exhaust dimensions and the hole spacing on the current S61K is still the same as the G60 meaning that any ST 60 size muffler will suit your application.

DerFly