I just went through the same thing on my 84 F2fiddy. The only way to get them out is to burn them out with a torch. While I was at it, I replaced all of the spring eye busings with eurathane bushings.

The bolts and self locking nuts are still available from Ford. Only thing is: they are about $12.00 each.

BTW: you could have saved some money by just re-using your stock frame brackets (flipped). Even they are still available from Ford for about $35.00 each.