sniped

Can I just make some out of this material or will it not work because it is a little thicker than the origional? Or should I use RTV instead of silicone?

Sorry, this comment led me to believe you had at least a piece of the
original gasket left.

Go to this link and ask these fellas. They are the Antique Small
Engine Collectors Club. If they can't tell you exactly what you need,
no one can.

http://www.asecc.com/

This link is to pictures of carburators and carburators and more
carburators..

http://www.asecc.com/data/briggs/carbtyp.html

This is a neat web site.

Dan