Roy,
If it is an OEM motor bracket, they were made by Garhauer. The newer bushings are made of bronze and they will sell you a kit. If you have the old plastic bushings in your motor mount that means there are aluminum spacers inside the tubes, they react with the stainless bolts and explode (expand and seize from the corrosion). A real PITA to get them out, but it can be done. Some pics and details are in my resto thread., look on pages 11, 12, & 14.