Check these vacuum diagrams to see if you can figure out which line fell off
http://www.amceaglenest.com/~iowaeagl/guide/index.php?title=Diagram_Section#I-6_Eagle_Engine_Vacuum_SystemsI'm guessing the one that came off is for the heat riser vacuum motor. The line should go from the vacuum motor, a sensor on the bottom of the air cleaner, 1 hose in, then 1 hose out, and onto the driver's side back of the carb.
Vacuum leak would cause running lean, what's it doing that makes you think its running rich?
What is the difference between running cold and hot?
Finally, if all else checks out, you could try adjusting the main air/fuel ratio adjuster, which is the main metering rods. They are located underneath the little cover plate on top of the carb that is secured with 3 little screws. There is a gap between the top piece and the vacuum piston that should be measured, and adjusted to spec. If you just want to mess with it a bit, mark the position of the adjusting screw on the top, so you know where it was before you adjust it, then turn it counterclockwise to lean the mixture.