I would assume if you have wheels that dont stick out of the fenders, then you would maybe be able to run 31's. I have 31" tires on mine with a 3 inch body lift and the front tires stick out probably 1 1/2" - 2" and i had to cut the fenders a little bit in the back, doesnt look too bad and pound in some metal inside the fender a bit too. I also turned my torsion bars up a bit too. if you dont want to modify anything at all, i'd say go with 29's or maybe 30's
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1980 4x4 LUV, 3 inch body lift, 4.56 gears, 31x12.50r15 Super Swamper IROKs, Weber Carb, Electronic distributor,