Weren't the the mounts upgraded later on? I had a recall on my '68 Z24 around 1972. Some sort of straps attached to the mounts were to be wrapped around the exhaust manifolds to "hold" the engine down during strong acceleration (nothing was installed on my car because I had headers). I remember a few years later that I had installed a newer design front mounts..wasn't aware whether the mounts were tall or not.

Bill