In general terms:
Disconnect battery
Drain and remove radiator
Disconnect shaft drive to hydraulic pump
Disconnect power steering pump
Disconnect fuel lines
Disconnect engine electrics
Chock up under g/box bellhousing
Support engine with suitable lifting equipment
Unbolt engine mountings
Remove bellhousing bolts
Separate engine from g/box and lift.
You may need to adjust height of g/box to pull engine forward.
Hope this gives you a guide.
Mr. Toad, March 2009
defentaly a 3Cs manual clutch
martin, March 2009
Are you sure its a Mk. 1, 1981?
3C's/3D's up to that era, and early 3CX's had power train trans. with torque converter, not manual clutch.
Mr. Toad, March 2009
edit
I can answer this question...
how to change the clutch on a mk1j.c.b with a 498 engine?