never mind just seen it all they did was change the openings on the ports on the sleeve and crank to change timing around, by doing that u can change the powerband for more top and less bottom or more bottom less top, but if u look at the specs for all 3 motors the bore and stroke are all the same so the cranks are all the same far as size just the cuts are different and its really the same crank as the 2101 just in the 02 and 03 they used a different dlc coating so the 01 has a different part number.