You also have to remember that ALL cars were required to switch to a returnless fuel system in 97 or 98 and therefore there are minor differences in engine management. This was done to reduce evaporative emissions (my 95 Sentra, IIRC, has a return line ). Nissan also switched Sentras to a close coupled cat in 98 on all Federal models, and the ECU's are slightly different. So, the short answer is, the basic long block is the same but you will need to switch over all of the ancillary pieces from the 98 to the 95 engine in order to make everything work properly....ESPECIALLY the fuel rail and lines! I would just get a set of intake and exhaust manifold gaskets and swap the manifolds as complete units onto the new engine. That way, everything will bolt together without having to figure out what needs to be changed. Also, if you have a stick car and the donor car was an automatic, don't forget to install a pilot bushing/bearing in the crankshaft before you install it. If it is a bushing, DO NOT lubricate it or it will come out and possibly enlarge the hole in the end of the crank it seats in! (This happened to me with a Chevy 406 in a 84 Camaro, so I speak from experience).