318 to 340??

The motor mounts are exactly the same. I don't understand why people keep repeating that bullshit myth. The mounts are ALL the same. Now, the motor mount engine BRACKET for the 340 and 360 are the same, meaning they are different from the 273 and 318. So, you will need the driver's side engine BRACKET for the 340 or 360, but the mounts are the same.
Oh Good Golly Miss Molly yes you're correct the bracket not the motor mount. I was using the wrong terminology my bad yes the motor mount is just a flat piece of rubber with a bolt sticking out of each and offset. The bracket that goes from the motor to the Rubber Biscuit is different unsung small blocks on driver side. I had to modify the driver side when I went from a 318 to 360. But since then I found the correct one and put it on. You should be a technical editor!