jbiol, if you fill in your Profile you will get more precisely wrong answers to your qustions!!!!
What size tyres would work for you will depend on the engine, transmission and axle ratios and what you intend to use it for.
In general 31" tyres are the largest that will work on a stock average 1984 CJ.
33" tyres will require some extra space but could work with the existing body if some more clearance between body and axle were achieved. A few members report rubbing issues even when lifted so you may not be out of the woods with just a small body lift. It is an inexpensive mod to fit 1" spacers with 33' tyres which will give you an additional 2" overall lift on the body, 1" under the diffs and better entry and departure angles. Whilst this is all good news it will be self defeating if your axle ratios are so puny that you will struggle to pull away.
Also be aware that 33" tyres may not actually be 33" in diameter. It is worth checking the physical size of what you are buying.