chevy042,
Just a follow up reply after a conversation with another Bolter yesterday.
Are the wiper motors you have by chance electric??? If you could remove the inside of cab access covers and take/post pictures it would help identify what you actually have and possibly point to a vendor or source for wiper arms.
Original wiper motor was a vacuum operated unit, so it appears a previous owner may have changed to some sort of any electrical unit.
Looking forward to more info so we can try and help you resolve your dilemma.

Dan