eddiech: Thank you so much! Those little holes in the taper head bolts were so filled with crud I didn't realize what they are.

The material I'm trying from McMaster Carr is item #1460N16, High temperature silicone rubber sheet, 1/4" thick, 70A. I bought a 6" square sheet. I'll report on how it works out. I hope in the next week or so.

Nice to know where parts for the mount can be bought. After reading the above posts, I decided to make my own rubber blocks from this material.
I flew my Typhoon with a Webra 1.40 for at least two, perhaps three, seasons in pattern competition and never changed the blocks after many hundreds of flights. They seemed to hold up fine. The plane has been sitting unused for about five or six years and the blocks were completely disintegrated.

If this does not work out, I will probably bite the bullet and mount an OS 1.60 two stroke which I have along with a Hyde mount, header and tuned pipe that was going into another plane I've since decided not to build. It will be a big project and require major surgery to do that. I may even have to make a new cowl. For me, it will be worth the effort since I built this plane using wood, including the wing. I also think it the best looking pattern design ever.