I made the swap in my '50 3600 but I was going back with the SM420. It is a pretty easy swap, you end up reaming the holes a touch and it fits perfect. I will say this the later mounts have a lot less vibration than the stock 47-53 style.
https://www.flickr.com/photos/advance-design_parts_co/8129099972/in/album-72157631867396207/
https://www.flickr.com/photos/advance-design_parts_co/8129071781/in/album-72157631867396207/