OGTS had them or all you need to do is to form some light gauge steel affix to the motor mount to create an air gap to protect the mount from the heat of the exhaust pipe. I have a couple but they have seen better days, the heat speeds up the oxidation.
These guys have it, apparently in stock. I have used them in the past for a small number of sheet metal parts that I could not find elsewhere. The only hitch is that it is a German firm and, as I have reported elsewhere, SplendidParts, also in Germany, suddenly is no longer able to ship to the USA, and the same problem may afflict this outfit. But worth a try.