[Rugratman]

Miker, on my 67 GTO, I used a quick ratio box, out of a Grand National, Got it at Napa, Bolted right in, They will need your old as a core.

Now, I was given the tip on the grand national box, by a poster here, but it might be the same as other GM quick's. Drives like a dream. No mod's will be needed.
You will need a pitman arm puller too, Napa has them too, even though Jegs/ summitt has them too, and they are cheaper. I only used it for about 1 minute anyway.
I needed to get a new rag joint too, but PY has them.
Happy Steering.....Very easy to do.