What will you be pulling the cultivator with? If it's the tractor pictured under your name, I don't think it will even pick up a rear mounted 4 row cultivator, they are pretty heavy. You might be able to use the tool bar for the cultivator, and take the plow gangs for the outside rows off and be able to handle it, but you may even have to go down to one row. I know that the WD Allis we farmed with could pull one, they used to pull them all the time with WD's and WD 45's, but anything smaller they either used two row front mounts or even one row front mount cultivators. I believe that the old 2N through 8n Fords came with a back mount two row cultivator. You are probably going to need 40 horses or more for a 4 row.