Looks like the '73 Verts were definitely lowered while trying to eliminate a vibration issue. The pads for the non-convertibles are much taller, looks like at least 3/4". I followed your advice and picked up a set of Westar EM-2370's and drilled out the rivets on them as well as the rivets on my original '73 Vert motor mounts and flipped the pad from the 2370's into my original clamshell. I roughed them in the other day to see how they would fit and it is perfect! I just need to go pick up some grade 8 bolts the proper size and I am off to the races.
Final question; there seems to be a lot of room in there with the new rubber. The old rubber was stuck to the inside of the clamshell pretty good and I had to chisel it then wire-wheel off the residual (what a stinky mess). The new rubber has a groove in one side so I am assuming that groove is a locator for where to set the rubber before clamping down on the clamshell. Is that what you recall, or can you simply glue and install? Any recommendation on the type of glue to use to bond the rubber to the mount so it doesn't slip around under operation?
On a side note, It was way easier to install the headers when I pulled off the motor mounts. This is just a test fit and I have work to do on both the mounts and the headers so I will either be lifting the engine/and trans again or pulling them again to finish off the work. Sounds like a lot of work but it's way easier than trying to contort your hands and fingers to get the header bolts tight enough.