Check the posting over on the Vintage Chevrolet Club of America (VCCA) site there was a tech tip a while back about replacing the cork seal with a large O-ring. Know a few friends who have tried it and have had no leaks or drips with the O-ring. Ask the JunkYard Dog I think he wrote the article. If you don't get a response I will see if I can locate the article for you.
Link:
www.vcca.org/forum
