Hrm, I know it has been a while since you posted this but I figure, better late than never.
The PB blaster should have helped loosen it up considerably. If it didn't work, it is possible that you warped something by heating it with a torch.
This looks to me like an old Galt stem (hard to tell from the outside). If it IS then it is extremely likely that the torch did some warping, since they had a notoriously thin brass casing.