Those disc coulters will work just fine in sod. The idea is that they help turn the sod (or trash for that matter) so you don't need the extra trash turners on top of the moldboard, thus the plow takes noticably less power to pull. Proper adjustment is critical to get the best performance. We had a 4 bottom JD plow and a 5 bottom 575 oliver plow. I could pull the 5 bottom oliver with a 1650 as fast as my Father could pull the 4 bottom with a JD 4020. Limit your plowing speed to around 3.5 to 4 mph in sod. You will be able to tell if you are going too fast. You will start leaving sod on top.