the intake cam is the only one that is different. The exhaust cams are the same on bothe engines from what I have been told. It is a good upgrade if you have them. As far as buying a used engine, make sure all of the main components are on it that you are going to need to make it run. If you are going to rebuild it any way, you will be putting in new seals, piston rings, bearings, timing belt, gaskets, etc. Chances are that for 300 dollars something is going to be missing though.