The riceburner crowd uses pourable polyurethane to fill in the pockets or to completely replace the rubber in a worn-out mount.
One last thing: I would not recommend using The Right Stuff for this task. A tube of Tremco Polyurethane Roof Sealer might possibly work, though.
R.
Kinda funny.
When I was playing with 2.2 turbo cars in the early 90s we would fill the voids in the front mount with black RTV. Cheap, quick, and easy.
If you're worried about release agent residue on the mount you can rough up the openings with a small file.
