can a 1998 saturn 1.9L SOHC engine replace a 1999 Saturn 1.9L SOHC engine
If you get no joy here try a Saturn, or even a model-specific, board.
A boneyard will have a cross reference guide. They should be able to tell you.
I am curious, do these guides have a lot of detail? I am sure that they will tell you if an engine will swap outright, but will they also let you know if the long block will interchange if you keep all the original sensors and manifolds?