non starting 97 Legacy 2.5 4Cam

It has to be something fairly basic, if you don't even hear the starter 'click'. Are you seeing 12V on both starter connections to the engine body? One leg should have 12V on it at all times. If not, be sure to check the check the ground connection to the engine or the battery connection. If you don't see the other 12V when starting, check fuses, links or you may need to trace it back to the ignition switch.

Remco

Considering it was soon after the engine work, I'd especially check connections that were disturbed to do the work. That's just about the right amount of time for something to work loose.

Mike

Don't know what you had to take off, but on my Impreza I had a similar problem after having the clutch changed. I even changed the ground cable, but the problem continued. Turned out the ground cable connects to a bigger plate also connected by only one bolt, on which the bolt had been left out a good half inch. When I connected the ground cable, it felt good and tight. It worked fine most of the time but sometimes didn't have a good enough connection to charge or start. I was baffled for 4 months after that clutch change.