Hi Kip´s41,
when I was solving the same situation than you, I used three differents kinds of vacuum wiper motor to adapt them to work. Too short strokes, too long strokes, poor power, etc. At the end, tired and frustrated, bought the electric one on classic parts and my problem ends, of course, after expent much more money and time.
My advise: use the specific motor for your truck, whatever electric or vacuum.
My truck is 52 chevy 3/4ton.
Alfonso
