if its 4WD it's the newer gen Vortec 4.3. It seems to be the only good point on the vehicle though. The gm downfalls on these are ball joints (like every 15000 miles), and of course the normal gm alternators, water pumps, head gaskets, hazard light switch, etc. In 96 they went with a fully electronic version of the transmission and there was a problem with the valve bodies. after driving for a while on the highway, you would notice them slamming into the next gear so hard your neck hurt, and of course this was damaging the transmission. It wasn't heat related either, because if you shut it off at a red light and restarted it it was fine again.
All that being said, the price does seem to be right. And I am a believer that if the price is right, almost any car is worth having.
Watch out for broken vacuum lines in the extreme cold that cause the transfer case not to engage, easy fix, but annoying if you need your 4WD.