depends if you ever done a clutch before, if your doing it, and what tools/working enviorment you have.
You should do it in a day on your back in the drive easily, providing you have a good supply of tea and toast...
On a ramp with air tools, less than 2 hrs.
Only difficult-ish bit is summoning the strength of ten tigers when 'twisting' box off, as the O/S driveshaft flange will hit the back of the fly-wheel.
Oh and buy a new green knock on cap for the end of the box, and a 'push-rod' seal for the input shaft, as these often get overlooked (they are tiny) and are the biggest cause of clutch slip in older motors...
Cheers
kraM