well if im not mistaken white smoke is generally coolant which would indicate that when you overheated you either roasted a headgasket or warped one of your heads. Just cause you dont have oil in your coolant or vice versa doesnt mean that you couldnt have toasted something in the head gasket/ head area. I"ll wait for one of the experts to jump in but thats what i would go with. I would try to do a leakdown test and see if you are losing compression on one of the cylinders if that is something you are capable of doing. Sorry to hear of your misfortune
