The 33's should fit in the stock openings if your suspension hasn't sagged. The previous owner of my 89 had 38. 5's on it with about 3" of home grown lift and the front wheel wells cut. My 33's look small now. Forgot to mention he was carrying a Boss 8' V-blade on the front with the 38's on. I'm probably going with the 305/85R16 Buckshots when I replace my tires, depends what we end up with for a tire franchise at the shop.
If you want the lift, check out Rocky Mountain Suspension at rockymountainsusp.com . They had the most reasonable prices when I was looking for lift for my 79. Make sure to tell them you have the deisel as the kits are different.
Welcome to the club, enjoy.