Thanks for the link 68Zproject.
I'm wondering about the #6476736. Do you know what the numbers on the gear box (1:.777) designate? I'm guessing that these numbers refer to the gear ratio of the box. The few gear boxes I've seen for sale don't have the #6476736 on them. Is that number the GM number? Will the #6476736 number be a 1:.666 or 1:.777 or a different one? So far, the gear boxes I've seen for sale don't have part numbers listed with them. The just show pictures of the unit and the numbers on them are 666 or similar. If I new which gear ratio I needed, I may be able to find one using that # if the GM part # isn't listed. From what I have read on the page you refered me to, I believe I need the 6476736 gear box for my COPO.
Thanks for your help!