I recently bought a 1998 Auto Discovery with a 3.9 V8 and LPG conversion but with a duff engine as I had a spare engine in the garage(like you do). The engine that came out is a Serpentine but the replacement is a Non Serpentine. Can I put the pulleys from the serpentine engine on the Non Serp and run the Serp belt around the ancillaries? I have a feeling that you can't but cant remember why. I know that the nose of the crank is longer on the Serp but seem to remember that is something to do with the oil pump??? Any info greatly appreciated.