[Mark IV]

There are aftermarket mount with Polyurethane instead of rubber, but what JBo said was right, the convert mounts are different as Ford needed to control NVH more on a ragtop. Even on the early (60s) Mustang converts, the engine mounts were different.

Understand that Brian did things based upon input from Ford and with the "flexi-flyer" AC frame, you don't want to tie the engine down too much as the loads will be fed into parts that were not intended to take such stresses.........