I just bought a 1974 franklin cable skidder with a detroit 353 motor. It was running fine when it was parked a couple years ago. Went to start it up but the motor won't turn. With a breaker bar it will rock a little but won't turn completely. Poured some marvel oil in through the exhaust side and letting it sit overnight. Will try turning it again tomorrow. Any thoughts on where the most likely problem lies? I'm assuming the internals are corroded and rusted due to sitting. Is it possible to get it running again or am I definately looking at a rebuild or a new engine? Thanks for any input.