That Photo was taken back in 1984. Marks 69 has a 4.56 Ratio. You outta feel it pull, it puts the 302 right in the powerband and keeps it there. I recall throwing fan belts off of this animal 15 years ago-that is how fast it rev's up. Having driven both of these specific cars I would have to give the nod easy to the 69 on acceleration, the 70 on the top end simply due to the gearing.
I have kept track of the RS Z over the years. Here is a more recent photo of this fantistic 69....
Phil
