there should be a number of old coulters thrown in the scrap pile somewhere. give a good look see at local scrap yards.
here is a picture of my mf 62 plow 3-12"
i just installed new coulter blades last year.
but over the years i have taken the coulters off/on a number of times. These plows have a small throat and will choke up easy, if you have a lot of trash on the field.
They do a great job on a clean field.
2-16" will roll and cover the ground better and have a larger throat area to allow trash to feed through.
I had to borrow 2-16" ford plows last year to roll under my garden truck patch corn stalks.
If you really want to roll some ground, get you an old mf disc plow, this old boy will really break up the soil.