Those tires will fit for sure with a 6" lift. You might want to get something in a 35" since those are a 34.5" tall. Really you can go close to a 37" tire with a 6" lift on a 07 ram. I have a 6" on my truck and it has 35s on it right now, I believe a 37" tire can fit but it WILL look stuffed. I just think those tires your looking at might be a little small for your truck. Something in a 35+" to a 36" would look good on your truck. You have a 17" rim so you have lots of choices out there.
Here is my truck with a 6" lift with a 35x13.5x20 tire