My vehicle base is a 94 Ford F700 It came with a 190HP 5.9L Cummins diesel and 6 speed manual trans. the trans is not a Overdrive just 1 to 1 in high gear. Of course i tuned up the power a bit at the fuel pump. All mechanical no computer on a 94.

I thought about going the stealth box truck route. What motor and tranny are you running?