About where I read that a c*x baby b could made to run inverted by looping a piece of fuel tubing from one vent, around the tank to the other vent.
  Is this the way to do it? If not how do you do it?
           Thanks, Gil

Of course you can only do this with a Babe Bee that has a metal backplate with two fill nipples. Later engines had a metal backplate with one fill tube and a vent hole. Then Cox switched to a plastic backplate with one fill tube and a vent hole.

For the ones with the vent hole, you can cap the fill tube. Very little, if any, fuel will leak out of the vent hole because air is coming in.

George