[Rich Biebel]

A Road draft tube is what that was called and was on a lot of engines going back many years.

If you were behind an old car with one and they let off the gas coasting and their engine was a little worn, you’d see smoke trailing out from under the car from the tube. The idea was to create a little suction across the bottom of the tube to help vent the crankcase

They were pretty Sloppy and oil leaked out of there.

PVC systems replaced the RDTubes