if you do a search on this forum you will find you can drop a 04-06 motor in and everything works. you can drop a 07-08 motor in and have some minor work ie you need to use your intake manifold from the 04 and the throttle system these are all aveo 1.6l engines.other motors that will fit would be 1.8l-2l from chev optra but you need at least the computer and probly lots of other parts.any gm opel engine could be made to fit also.any engine other than the 1.6l will be more work and some mechanically inclined help.