Arctic cat 300 engine compatibility?

i am looking for an engine for my 2002 arctic cat 300 4x4, what years of this engine will fit. or what website can i find this information at.|||00 01 02 03 04 all of the motors are the same for as the mounting of everything so if you could not find a 300 you could go sizes up or down long as it is 4x4 and air cooled hope this helps