Hi all, This is my first posting. I have a 1977 F100, inline 6. She was running fine until recently. But now she runs real rough, and there is a lot of smoke coming out the tail pipe. It's darker in color, so I don't think it's water vapor. Anyone have any ideas what could be the problem? Do I have a blown head gasket? How can I test? Thanks much for any advice.

 

Sounds like to much fuel. Check air intake for restriction and filter condition, check for correct choke operation, carb float level.