if i remember right from when i tore apart the 235 out of my 55 2nd series that you can not take the timing gear cover off without droping the oil pan cause there was two bolts that screwed in from the inside out other wise its posible that there might be oil in the bolt holes that would make the bolts losen from the vibration from the engine its not likely but hey anythings posible
Nate


Link to my photobucket for pics of my vehicles
http://s238.photobucket.com/albums/ff17/OldIronChevy/