IH Farmall 656 gas/ IH 240 Utility/ 2, Super C Farmalls/ 2, Farmall A's/ Farmall BN/McCormick-Deering OS-6/McCormick-Deering O-4/ '36 Farmall F-12/ 480 Case hoe. '65 Ford 2000 3 cyl., 4 spd. w/3 spd Aux. Trans
If you can post a picture, it may help. You don't say if it is an older, or newer plow... 3 pt., or pull type..??
There are usually part numbers on the back of the moldboard somewhere. You could always Google that number, and see what pops up.