school me on motor mounts...er the rubber part.

Not sure just how many different flat style "insulators" were made for the slant six, but there is at least four. Don't forget the slant was used in other body styles, beside the "A"s These are the OEM part numbers for some of them.
1960 Valiant right 2121 733
left 2203 040
1961 valiant right 2203 039
left 2203 040
1962 valiant right 2264 140
left 2265 018
1963 valiant right 2264 140
left 2265 018
1963 convert right 2406 708
left 2406 705

1964 Depending on body
right 2264 140
left 2265 018
right 2406 708
left 2406 705
right 2264 674
left 2264 675
right 2406 672
left 2406 674
You get the idea