I agree on killing the tranny with a canned tune like that.man your killing your transmission and loosing horsepower! Ive used matt @ gearhead and vivian @ quick trips. Vivian is like 50$ and a world of difference over a canned tune.
http://www.quicktricksauto.com/60l-ford-superduty.html
You can see a world of difference with a custom tune done right.