After much thought, can this be for the heat box for the manifold/carbureator? If so, I don't have one on this setup so it is just a question of plugging the hole with some sealant and tightening the gasket and manifold flange tight.

Last edited by Jeff Mitchell; 11/12/2013 12:48 AM.
"If you're not living on the edge, you're taking up too much space. Life is short, eat desert first."