Actually the road draft tube dropped down on the passenger side as seen in the image:
[IMG]http://img718.imageshack.us/img718/1170/283g.jpg[/IMG]It is easy to access, being on top of the block right behind the intake manifold. It attaches with a long bolt right through the top. One of the bellhousing bolts captures a tab near the middle of the tube to keep it in place.
The concept of the road draft system was that while the vehicle is in motion air flowing over the bottom of the tube would create a draft drawing crankcase fumes out of the engine. The failing in the design is that if the vehicle idles a lot, or drives at very low speeds (like a milk truck) a sufficient draft was not generated to clear the fumes. The result was that early engines with this system were frequently packed with sludge so thick it could plug up the engine.
In the mid 60’s before the grommet was adopted for the pcv valve, early pcv installations used a metal adapter that attached with a bolt through the top just like the draft tube, but they had a hose nipple for connecting the smog valve.
