John: Thanks for the information confirming the venturi size. I have switched my 40 and 60 carbs and now have them where they belong. I did get a modern swivel ST muffler with my G60 so at least I've got something for it. But I can't bear to use it on a vintage plane, whether pattern or sport, so I've been searching for a closed front Semco with no success so far.

That is a nice collection of G60s. In a perfect world I'd be mounting my NIB Bluehead on my just-completed Ralph White Fliteglas P-51.

Jim