Silverseal...
19224 Allen Rd., P.O. Box 1050
Trenton, MI 48183
Phone 734-479-2255
They sell new ones... I got one for the ex's 65 Dart shipped to my door for just under $200 and it arrived in three days (they said they were back ordered and would ship from vendor)...
It's better to get a new one as most of the old ones have those characteristic cracks...