According to the Service manuals for AC and Deutz nothing. The late N6(basically Series 3 and newer)are the same as the R6. The first noticable change came with the R60 w_Deutz engine and other internal changes. According to the specs released by AC and Deutz the R60 has less capacity than the N_R6. The R62 was increased again to the R6 size. Not sure if this was just different ways Deutz was figuring capacity or what. I do know my Hyperized N6 will out perform the neighbors Hyperized R60. And won't keep up with the other neighbors Hyperized R62, but then it has more HP.