Dude seriously do what Merc is telling you to. That thing is NOT safe the way its set-up. Those axles Im surprising havent buckled in yet, I tell people to swap to 60's at 35" tires, 40's should never go on stock half ton axles! They are NOT designed for that! Whoever told you it was built right must have been high Im sorry to say. I dont even wanna know what gears are in them... from the looks of things Id be willing to bet they were left stock.
For that set-up I would def go with Dana 60 front, Dana 70/80 rear , Ford cross over steering (Mercs suggestion), Long arms (short arms should be NOWHERE near that set up), extended brake lines, drops to pinion angles will be needed (I dont know how to drop, hopefully Merc can tell us), limiting straps should be on there, a good adjustable track bar, a stronger steering box, rock solid ram steering fix. Go to my build thread and read that, link in my sig. I am planning to lift to 7" and go with 37's, you can get build ideas for what you will need in there. I would also ditch the boggers, Interco tires suck mileage/ on road wise.
Whats the worst that could happen? Well its not a could with that set-up its a when. And that when is when your steering snaps and you lose control of the truck. That is when your axle buckles in and you lose control of the truck. What happens if you lose control while your at a high rate of speed? SMASH right into some innocent soul's vehicle and they get hurt or even worse killed. Dont leave it and end up hurting someone, fix it and do it right. Youve got a great base to work with, just need to set it up properly now.
My 2 pennies.