There are some steps needs to be carried out from underneath.
Remove the small cover plate between the engine and the gearbox
oil sumps, it's fixed with three small bolts (you can see a part of the
flywheel now). Unbolt the engine side support, this is fixed to
the cylinder block with 2 bolts, and swing it out of the way.
Without removing the engine:
You'll need a jack to lift the rear side of the engine a little bit.
Lifting the engine at the oil sump would be obvious, but
recommended (even using a wood block between
the sump and the jack), the sump is not a load bearing structure.
You can put the jack under the centerline of the flywheel (simplier way),
or you can put two jacks under the left and right side of the cylinder block
(nicer way), in this case you have to operate the two jacks almost simultaneously.
Regardles the number of jacks i recommend to use suitable wood block(s)
between the jacks and the lifting points.
...So lift the rear side of the engine until you're able to remove the bolt (loosen earlier)
from the central support console. From underneath remove the pin from the gearbox rear
support, fixed by two bolts. From this point the drivetrain is held by only the engine front
support and the jack(s).
You can start to lower the jack(s) slooooowly, but don't forget to monitor the coolant hoses,
clutch slave cylinder hose, the fuel line at the pump. Check the clearance between the
distributor and the bulkhead also in order to prevent damage. Continue lowering until the
central support slides out of the support console. Remove the central support (two bolts,
one of them belongs to the starter motor, and one nut, see pics), then remove the three remaining nuts
which are holding the cylinder block and the gearbox together. Now the gearbox can be pulled
off (watch the gear selector lever [leva di cambio?], remove the bolts from the linkage if
I've made two pics which may help to identify some component / bolt locations easier (i hope).
When you decide to lower the whole drivetrain, you will need (much) more
ground clearance. You have to drain the coolant from the engine block.
Disconnect the front radiator hoses from the thermostat and the engine inlet.
Disconnect the coolant hoses towards the heating box, and the coolant reservoir
Drain the brake fluid from the clutch slave cylinder (do not reuse the drained
brake fluid, refill with dot4 class fluid when reassebmling).
Disconnect the clutch slave cylinder from the clutch master cylinder. Disconnect
the incoming fuel line from the fuel pump on the left side of the engine. Remove
the cabling from the starter motor, disconnect the cable from the alternator (to do
this remove the air filter housing and seal the air inlets).
Underneath the car remove the two small bolts which are fixing the engine front
support to the front crossmember. Lift the engine a bit. Remove the four
bolts wich are fixing the crossmember to the body. Lower the crossmember.
Remove the necessary bolts from the crossmember in order to swing out (or
remove the lowered crossmember completely). Remove the bolt from the central
support. Start to lower the engine to a suitable support which prevents the oil sump
from damage (still not a load bearing structure). While lowering check the engine
compartment in order to not breaking / tearing anything. After the front section
of the engine is lowered put a jack under the gearbox rear support. Lift it a bit.
Remove the pin (fixed by two bolts) lower the rear support. Now the whole drivetrain
is removed from the vehicle.
If you have air conditioner then you'll have to unbolt the compressor. Place a wood
crossmember across the engine compartment and with a suitable stuff bind the
compressor to the wood crossmember. So you can save the refigerant.
When the engine and the gearbox are separated i would recommend to
check the clutch...
Damn... that was long... i hope i didn't missed anything.