Im not one for the "fine" details on such thngs but as far as I understand,,, a c8 and an l8 are similar machines both having the swiftmatic transmission and the Gravely T head engine just at some point in production they just started designating them as convertables, Im sure someone who is more into the minute details will correct me or shed more info on the differences. However if you are refering to the Kohler powered commercial 8 then there are alot of differences between the two.