02 Ram 2x4 v6...Went from stock 17s that ran straight as an arrow, could drive for miles and not have to steer, to factory 20s that pulls to the right greatly. Had a full alignment done yesterday, and they told me that my camber is maxed out, and it still pulls the same amount to the right...Now what?

 

Have your wheels and tires ballanced. Also check the tire pressure.

 

^^^ what he said

 

I have an idea that most people over look. Remember how wide your stock tires were? Now compare them to the new tires. Are they wider? Wider tires tend to pull where there are ruts in the road. I'm not even talking about big visible ruts. Skiny tires like to stay in between the ruts, while the wider tires are too wide to stay in them.
I know when I went from my stock 265/70R17 to 325/65R18 the difference was huge. I know this is true in just about any kind of car that has wide tires. Especially sports car like corvette's and vipers.
Another thing that might be going on is the mechanic might not have adjusted for road crown. Areyour ball joints in good shape? Worn suspension can cause pulling of the steering past what the adjustments can correct.

Just my $.02