<VV> Shoulder Belt for Rampside

[Greg Shaw]

  I am interested in installing a seat belt with a shoulder strap in my 61 Rampside. I see Clark's has a generic one for about $50. I would have to mount a plate in the upper rear corner of the cab. Has anyone tried any of the modern belts that mount behind the seat and come over the seat back? How about a modern seat with the shoulder strap integrated into the seat and still fit in a Rampside (unlikely)? If you've had any experiences (good or bad) I'd appreciate your input. Thanks. 
  Greg