Power take off...pto. The newer style drive will alloy you to disconnect at pto for dry starts and easier to remove engine. The short drive is okay and I have one in mine now/as stated before interior built around it. With the short you will have to move the whole motor forward till drive line comes off pump vs disconnect drive off pto and only move bout 1/2" or so to pull motor with 4 point....if your building a close/tight fit interior near engine its something to think about now.