You can measure the width of your plow from the left side of the left beam to the left side of the right beam on top of the plow. Be sure to measure at a 90 degree angle to the beams-shortest distance between the left sides (or right sides, or center to center) is what bottom you have. A single 14 inch plow will cut 2 inches less dirt width in the furrow than a 16 inch bottom. A 2x14 will cut 4 inches less than a 2x16 plow. In other words, you have to cut and throw 4 inches more dirt with a 2x16 than a 2x14, and in hard or fairly dry dirt that makes a big difference, especially if you are about maxed out with your tractor size. I have heard a "general" rule of thumb of 1 HP per inch of plow bottom-2x14 will need about 28 HP. I guess sometime in the '70's when no till farming was being pushed by the thinkers of farming, everyone was going to chisel plows, V plow subsoilers, or they were planting no till for several years before loosening the land by one of the above methods.They sprayed the weeds down. At least they did it that way around here. Now they use super heavy disks to work their fields. I have a Ford 2810, 33 HP, bought new in '87, that I use for plowing about 6 acres a year, and the only problem I have with adjusting my plow just right is that I have a ROPS with a canopy, and I would have to remove the ROPS to get my tires close enough together to get my plow to hit the open furrow exactly right, and I really like the canopy. I'm only wide by about 2 inches, so I don't bother with it at all. You have to live with what you have. Hope this helps.