New Detent Plates for 1958-1960 Thunderbirds available.
Hi Jon, yes, the Detent Plate is still available. I can't tell you how much it will cost to ship one to you, but Marianne should be able to, as she has probably shipped these to your country before. I can tell you that they do not weigh very much. She handles our detent orders and can be contacted at: My59Tbird"at"gmail.com (replace the "at" with the @ symbol. When you order, you can do so from the Home page to her.
If you have not done so, look through the various posts on this subject, especially #64 and #61. There are other reasons, than the detent plate that can cause this problem and they are detailed there. It all goes back to having worn parts in the car that have never been replaced in the nearly 60 years life of the car. Even if you fix that problem, I always make it a point that when I park the car, I pull the emergency brake on because I do NOT want any unexpected problems with the car dropping out of Park and chasing it around the yard, as you said.. It is just something I do to make darned sure it does not take off on me.