I just measured mine, the interior is in the car and the block on the driver's side is 10 inches from the edge of the upholstery to the edge of the block and the block is approximately 2 1/2 inches wide.
Hope this helps!
My wife is putting in the Headliner on our 160B today, so I got some pictures.
Dims are from the left side rail (inside)
1st block = 6"
2nd block = 29"
inside to inside edge of blocks = 20"
block dims = 3" x 8 1/2"