Allis-Chalmers Model 80 4-Bottom Plow

I have pulled 4-16" with our D19 with no problem, and have even pulled it with our D17, the D17 just plays with 3-16", around here we have heavy black dirt.

I am assuming that your JD 5320 is in a "compact" tractor catagory, yes it has 65 PTO horsepower but they are pretty light on their feet, I think you might want to drop down to a 3 bottom or even a 2 bottom to do a better job.

We pulled the 3 bottom in sod that was plowed a couple of years ago.  It did well.  3 bottoms in sod with brush roots with no coulters was TOTAL Waste of time.  Also the soil was dry - unusually dry.  

I agree - based on the fact we plowed pretty easily with 3 16's in soil that was turned recently.  The fields that have just been mowed for years with brush and tree roots was a challenge.  We found used coulters now and the shin for the mole board so we'll be in better working order for cutting sod and roots.  Like I said in an earlier post - I guess I'll just have to get a bigger tractor - oh dear 

there are a lot of variables, weight of tractor, soil type. compaction, ect. i have a 5210 and believe me even though they say it is 45 hp, 2x16's is all it wants in stalk ground and when i move to sod i go with 2x12s with the 5210, while i can take a old 46hp model 961 ford and pull 3x14s right beside it in the same field

 now i know that the 5210 is not a 5320, but they do run the same enjine a 179 ci diesel, and the same transmission,the 5320 is getting its extra power from the turbo,

there will be times when the 3x16s will give the 5320 more than it wants

 

the tractors pulling 4 bottoms in black prairie land, like the corn belt, will struggle to pull 3 in hard rocky red clay, like here in central ky.

 

  time of year, and soil moisture also comes into play, a piece of ground that you can easily plow in november or febuary will pull the crap out of a tractor after a long dry spell in the early summer.

 

by the way 4x16s will work the heck out of my old 4020 jd, and i want even think of using one in sod with my 6060 allis, (63hp) , while i can run with 3x16's

 

so my suggestion is to find you a set of 3x14's or go ahead and trade the green toy for a real tractor,

An old employer of mine said that you need 20 HP for every bottom on a plow. I told him he was painting with a wide brush when he made that statement. Yes I think 20 HP per bottom would pretty much cover any plow with any soil condition but like others have said there is a lot of variables to consider. We had a 59 D-17 that could pull our 4X16 plow in black dirt. The D - 19 did not even know it was back there.