something else i want you to try, is if it wont roll over clockwise when looking at it towards the front (just like your trying to tighten the crank bolt), try going back a little. see if it is bound in a spot, or just locked up totally....this is only if it wont roll over. Honestly, it sounds like a possible wiring issue to me (fingers are crossed) as usually there is a pretty big bang if the motor itself is locked up...not just a starter clank hitting the flexplate...