The puke tank was an attempt to catch any vapors that condensed as
oil and drop them from the bottom of the puke tank back into the
oil pan instead of on the track. They had a draft tube that came from the top of the puke tank and out to the track for the vapors. If you ask the old guys they will remember an
oil slick running down the centre of the lanes as alot of road cars used a draft tube before the days of EGR's and other more environmentally friendly options.