Actually the 4.3's will improve the drive-ability on the street and will defenatly help you offroad, I ran 4.3's (came from the factory that way) in my 80. Of course in the stock configuration it didn't do much for it but that change greatly once a 5 speed trans was swapped for the stock 4 speed. There was definatly a difference, I ran both 31's and 33's and liked the difference.