340 engine mounts

OK, I understand that the driver's side motor mounts are different.

Are the biscuit locating holes different?

Are the engine tabs thicker on a 340 versus a 318 or vice versa and thus one of the brackets are narrower than the other?

I plan on putting a 340 into the car and I am trying to figure out if I already have the 340 mounts.

Thanks for any help.

Art