A Killefer ripper and Yonkers & Johnson plow

Late 1970's and all of the 80's, snow plows were "painted" with "plow wax", as often as one could between storms and before storing for the season. Shiny surfaces make huge difference in plowing snow, same with plowing or pulling disk in damp soils. For the "snow shovels" a good coat of "johnson's paste wax" worked wonders along with ensuring the shovel was left outside in the cold. - cts

How far have you looked for plow parts? There is a guy the Allis Chalmers people go to for hard to find stuff, The Plow Guy. But it could be Dave the Plowman, he is specialized in AC and maybe JD.

In the same search Tyler the plow guy , can fix your parts from Farm Show magazine. But that could way to old by now. So if your inclined search the plow guy you might get lucky.

the other thing that can be done is get out the angle grinder with a flap wheel and clean up the shares and moldboards before starting. It doesn't take long and makes a big difference to the initial few passes. But it's definitely easier if there's less rust to start with, by protecting the surfaces. I personally use lanolin (Woolwax brand) because it's natural and won't pollute the soil like waste oil does. Does a pretty good job of creeping too and is hygrophobic so you know no moisture is going to get near the steel