can I use lead to seal an exhaust leak>

I think if I was in your shoes I would try and wrap sheet metal/ pipe around it and clamp that

What instantly came to mind you talking about lead was "old school" sealing cast iron sewer / drain pipe. "Oakum" and lead. Made a VERY interestin' smell. My gramps was doing this when I was maybe 5 years old. I can still conjur up the smell