BBshark has it right, the measurement between the driver and pass side lower control arm centerline pivot point. I just needed to confirm my measurements before I welded things up. Thank you all for the help
Wow, 16.125, my frame is measuring 16 3/16" after I have done some repairs. I guess this is close enough as long as it is the same on both sides from the centerline of the frame. Thanks for the input.:thumbs:
Since they are mounted on an angle and the VBP mounts are thicker than the stock, my 16 1/4 measurement is slightly larger. So you are probably fine at 16 3/16