FYI,
The part number for the RA III is 7028270 and the RA IV is 7029270, these Rochester carbs are rare and very expensive if you can find one. I have a friend who pulled one off of an engine he purchased for $400 and sold it on ebay for over $2,000.
Good luck with your search, I would suggest that you contact a guy named Lars Grimsrud via
e-mail, he is one of the best all around GM guys in the country and he may be able to find you the correct carb.
As far as the tranny leak, check the fill tube o-ring and all gaskets.
