http://www.fordfe.com/index.php? This may help. Just from reading posts there it seems the castings were pretty good in 63/64. 64 blocks will backfit to 58 with no problems but 65 up cars need the 4 engine mount holes on the sides. So if you wanted to swap into 65 up you will have some problems with mounts since 58 to 64 only had 2 mount holes on the sides