I've had the car ten years, and only once before did I get the dreaded starter lock. I forgot the cure so I looked on here and found the below thread.....THANKS …third gear and rock...MOSTLY BACKWARDS. I actually have a Roadster so the spare tire gave me great leverage to rock and roll...I still work out pretty good so I grabbed the spare and actually was pulling and pushing so hard the tires came back...I was about to think about unbolting the starter when finally I heard the sound of joy!!!! IT RELEASED!!!
https://www.fordbarn.com/forum/showthread.php?t=310602&highlight=stuck+starter
https://www.fordbarn.com/forum/showthread.php?t=310602&highlight=stuck+starter