Hi, I have a 1997 Grand Prix with the 3800 series II engine.

I just bought it and put about 30 miles on it when my lights start flickering and the engine kills. I tried to get it to jump and nothing. Later that night I found out that it was my alternator. Next day I replace the alternator and battery and start it up. Alternator works fine but there was a horrible clanking sound in my engine. After about 5 seconds the engine just kills. I believe that there is either a connecting rod out or the pistons are just shot. I have a 2002 grand prix with the same engine also. This engine is in perfect condition. Would just swapping the engines out be more practical instead of going in and replacing the pistons?