Since this is in the handling forum, it's worthy to add that modifying your exhaust is a worthwhile thing to do to get modern day 16:1 ratio.....especially if you are running a smaller diameter steering wheel such as the Tuff Wheel.

I have the Fast Ratio in a few E bodies and would never go back. I have 24:1 power and manual steering in a few others and they will eventually go into the scrap metal pile along with my space saver tires/rims, 450 wheels, frame tie down brackets, and bumper jacks/j-hooks.