Radiator
#2
Take measurements, order from someplace like Summit or Jegs.
You may find an older all-metal radiator in the boneyard; I think I ordered one of the last ones available back when I bought my "Max Cooling" unit off RockAuto, since the current replacement is plastic tanked.
RwP
#4
You didnt say what year your truck is. I know the early radiators are different from the latter.
That being said, on the early, (as Ralph said ) you can get the wider 26in radiator. But I believe it is single row.
I have never found anything for aftermarket radiators, other then factory designs.
My suggestion would be to check measurements of yours and compare it to the aftermarket universal type. You may be able to put a 2 row in there, but it will likely take some mods to make fit.