Yo I have a 94 cherokee sport all stock I have a set of 33*12.50's to go on it what would I have to do to put them on. And also how bad would they kill my gas mileage? And how do they perform?

if your putting them on stock wheels you will need to buy wheel spacers or buy new wheels with a different offset. then buy a good saw and start choppin those fenders because 33s wont fit without a lift or some serious trimming.

alright so how big of a lift do i need. and wat should i get with the lift. should i go with springs shocks and blocks or what do i need

The minumim is a 3 inch lift with lots of cutting and bump stopping to keep a low Center of Gravity. Most people stay with 4.5 - 5.5 inches of lift with that size tire. Going too high makes it easier for roll overs.

you'll need all kinds of stuff over 4 inches of lift

Shocks
Extended brake lines
Upgraded steering
Track Bar
Cutting fenders for clearance
May or may not SYE but is recommended
You'll want lockers for sure
4.5 inches and up lots of people recommend Long arm kits but is not required
That's just a small list to get you started

Most say DO NOT USE BLOCKS!!! Some say it's ok. I've found that anything over a 1 inch block is N/G. You can get extended shackels to give you an extra inch if needed and it's safer. Go with full leaf packs. Your Jeep is a 1994 and if they are stock leafs they are tired and Add a leafs will only give you lift for a short time. You'll put all the stress on the add a leafs and wear them out.