67 Cuda 273 to 340, 360 engine mounts.

Use your 273 brackets if you still have them. Just requires 1 spacer on the driver's side.
340 engine mount bracket | For A Bodies Only Mopar Forum
If you don't have them, these ads are still up:
[FOR SALE] - 68-72 340 motor mounts | For A Bodies Only Mopar Forum
[FOR SALE] - engine mounts modified for 340 | For A Bodies Only Mopar Forum