Here is what I learned.

Old tractors are heavy.  Bought one with a 22 ft steel box on with hoist and you weight appox.  24,500-25,000 empty. Giving up prob. 4-6,000 # right there of grain cap.

Next you are going to have to put 20,000 #on the front and 34,000 on other rear.  Sorry, those front springs, ect. are not nearly made for 20,000. 

Second, nor or the rims or tires.  Going to have to go to the largest rim you can get and the largest tire with a cap. of 10,000.  Largest I could get was 9,200 or 9,300 I think, would have to look.  That is OK I cant get 20,000 on the front anyway.  Darn close though.  Believe me the DOT boys will look at the tire rating. 

So if you like hauling just 500 bu corn and 425 bu beans you are OK. 

I am running an old KW 1978 or 79.  Bought an old silage hauling truck for seed corn purposes mainly and use it for grain on the side. 

Oh, they did not double frame it all the way.  Only up to the back of the fuel tanks.  Frame broke on the left side.  Good thing the help noticed it and limped it home where we off loaded it before it went down the road and across those RR tracks.  Would have been beans all over the place. 

Other than that, it has been a dandy.   

P.S.  Those bigger tires just might rub on your steering linkage.