If it just leaks oil from the valve/Cam covers and possibly the intake plenum, why is he considering replacing the whole engine? Also, $1,700 sounds like ití* a used/salvaged motor as a new GM long block crate would probably be in the $4 - $5k range.
Regardless, I would seriously go look at this car before making a determination. If the guy is quoting $1,700 for a new motor, he not might be on ball about where the leak is. Valve/Cam Cover/Intake Plenum is all in the same general area, soÖ
Replacing the valve/cam covers is fairly simple, but the plenum is a little more difficult as the starter is housed up in the valley under the plenum, so I donít know ití* level of difficulty in R&R.
I had a í98 Aurora and while it was extremely reliable, when something did break, it was much more difficult to service than a standard GM product, so keep this in mind.