318 to 340??

What is the difference between the engine bracket and the engine mount? I ordered Schumacher slant6 to 273/318 mounts now with the change of plans I have to order the 340/360 what's the difference if they are the same?
On '72 or older, they have a rubber biscuit for the mount, and a metal bracket that bolts to the motor. the rubber mount goes in between the bracket and K-frame