i have a '99 Ram 1500 5.9L 4x4, currently stock tires, (265/75/16) and stock suspension. How much could i tow?

If you have an owners manual that would be the ebst palce to look. I triewd looking on the site I sue which is dodgeram.info BUT they don't have a listing for the 1999. For a 2001 model thoguh it looks like the rating is just about 7500 pounds. I know my rating with a 5.2L regular cab I can only tow 5000 pounds. So my best judgement for your truck would follow with it being 7500 pounds.

7500 lbs is the limit