The image in this post illustrates it:
http://www.ft86club.com/forums/showp...&postcount=467
With the seat pushed forward to allow for a rear passenger, the center of mass of the driver is 185-188 pixels from the front axle and 149-152 pixels from the rear axle.
That puts the driver COG only 55-56% towards the back, but the seat looks like it can go back another ~25 pixels. It only needs to go back 12-15 pixels in order for the driver and front passenger COG to be 60% towards the back. That diagram's scale is approximately 3.3-3.4 inches/pixel, so you could still push the seat back another 3.5-4.5" past that point.
It's an old FT86 concept II image, but you get the idea.