When those mounts were originally designed (probably about 25 years ago) they were intended for 120 4-strokes. The stiffness (durometer rating) of the original isolators may not be adequate for a larger displacement engine. McMaster Carr sells rubber in various durometer ratings
https://www.mcmaster.com/#about-rubb...dness/=1eadbhw
You might need to experiment a little. I used replacement rubber with a durometer rating of 60 for my mounts, but I was only running a YS 1.10.
Hyde mounts are, by far, the best way to go! Central Hobbies seems to be selling out their stock of Hyde mounts, not surprising since pattern is almost exclusively electric now. I think you can find Merle Hyde's email address there and he can probably still provide a new mount to meet your needs.