Actually we have never ventilated a 310 block but have had problems in the past keeping wrist pins in them. That problem was fixed as well. Add several inches to the oil pan and add a oil cooler.

Not sure if the 1600 and 1650 had the same motor or not, but we've had very few problems with our 1600, when I had it on our round baler I kept the black smoke rolling most of the time.