Tires for 2002 Silverado 4x4

I would like to get larger tires for a 2002 Silverado 4x4.  I'm told the largest I can get are 33's.  Can someone confirm this?  Can you suggest a brand/model that would give the best city/highway preformance?  The stock tires are P265/75R 16.  I'd like to go with a new 18 inch rim size.  Can you provide me with the exact dimensions of the tire so that I can search online for what is available?  I know that sounds stupid, but it would be a 33x XX x XX? is what I mean by exact dimensions.  Thanks.  

Thats correct.  I have an 02 1500 that i recently put 33s on and i dont regret it.  If you get those goofy torsion keys theyll fit perfect, but i just cranked my stock keys and trimmed a lot and they only rub on one side at full lock, and only a little bit.  If you do most of your driving on the high way  but still want good off road ability id recomend BFG A/Ts.  tire dimensions can be kind of confusing, so here ya go: standard sizes are in inches and they tell you the width, overall diameter and rim diameter.  metric sizes are getting more popular, especially for larger rim sizes, and they give the tire width in millimeters, the aspect ratio and the rim diameter ie P265/75/16. that means that it is 265 mm wide (10.5 in), each side wall is 75 percent of the width measurement and the rim is 16 in.  The P is for passenger tire, so you want to replace it with one that says T for truck tire.  i think the size you want is 285/65/18.  you might need to search other aspect ratios tho to see what available, im not a fan of the big rims so im not sure whats out there for em