ok i have an 84 f250 with no lift on it and 33 in tires now.. i want to convert this to tractor tires.. but this is a new one to me, what do i need to do to get the rims on it and how much lift do i need.. any ideas?  

Carlisle makes 12 x 16.5 10 play rated tractor type tire that will fit on 16.5 inch rims that were main stream on HD pickups until mid 80's. Part number is T51S3J7. They would also be about 33's too and be able to easily handle weight of truck and the 10 ply carcass would take a lot of abuse too. Tractor tires are not good for high speeds and are not good on hard slick/wet surfaces either so I would not go this route if you plan to drive in on wet slick roads or at high cruising speeds.  

Why in the world do you want tractor tires?  

In mud and soft ground a tractor tire has no peer but they do have greatly reduced street qualities.  

look at the ag tires like they put on a fertiliser spreader truck. it floatation your looking for right? Like snoman said though, they have a limit of 55 or so,just too much surface area to keep cool,they run water in them for a reason. firestone goodyear i think kumho have a version up to 50 to 60 inches tall, they are a v block tread,there are other turf saver tires that have a horizontal tread block pattern, look at an ag implement shop,J.Deere etc.
now your gonna heve to have some big brakes...period,were talking over a foot here more like 15 inches and up to be SAFE and be able to stop.there are also the tires that the large grass hauler forklift use, they run 35 to 37 inches high and look like the ground hawg type tire,they look tough too
luck to ya