Can any of you help,I have an IO-320B1A and im trying to sort out which size prop bolts i have they are marked A988 3 LFC .Any one know what size these are.I have measured the Plain shank which is about .4" the thread is abaout .430" but the internal of the prop flange is about .375 that is inside of the protruding sleve which is about .6" outside dia.I am about to order my Prop so don`t want to get the wrong one.