It is quite easy, but one of those jobs that is far easier just to give to an Alfa workshop that attempt to do it yourself... that is I assume if you are doing it in car.
It is years since I have done one, but from memory:
You need a fair bit of room under the car (that is, a hoist helps).
- Ensure you have the right size on hand. There are two different sizes.
- Drop the exhaust at the bottom of the exhaust manifolds so you can tilt the engine back.
- Undo the rear mount nuts.
- Tilt the engine rearwards with a jack under the front of the sump as far as it will go (without damaging anything). There are two spacers in between the mount cross piece and body. Note where they go and do not loose these.
- Drive the old mount out sideways with a drift (on the metal sleeve) and a hammer. Ensure you do not mark the bore.
- Clean the area up of grease and oil. Heat the area with whatever you have. One of those bunnings heating torches would probably do (an oxy Acetylene is what I used to use). The mount is size on size with the bore, so heatiing will allow you to slip the new one in.
- When the casting is hot enoung so that if you spit on it, it sizzles, slip the mount in from the side with the most room. Doing this with welding or gardening gloves hekps so that you will not get burned. Make sure you line the orientation up the same as when it came out. Have you drift and hammer on hand if you get it a bit cocked on the way in. Sometimes the last bit you will need the drift and hammer with anyway.
- Bolt it all back up.