Don't know what smell you are talking about but you are suggesting some weird remedies. Assume you mean exhaust: The fix for that is fix the exhaust. Pipes, connections, rust outs, gaskets, tailpipe location, manifiold leaks. Then seal the firewall. Seal air vents, heater vents.
Motor may have excessive blowby. That would be a separate issue.
Or you may be taking about gas fumes. Leaking carb, lines, gas tank or cap vent issue, etc.
Also, some of us like a little bit of those smells.
You must identify what you smell and where it's coming from to get meaningful help. None of which will be too close to your suggestions. Many folks here have probably had these issues with Pre AD, AD and beyond.
