copy-paste from SF:
It's not that hard, just quite some work to get to them. I assume the head is still on the block.
- take out the cams, follow the tsrm for that
- on the piston you will be working on; remove the sparkplug and turn the piston to bdc.
- feed a long enough rope into the cylinder, about 4' will do, and leave it sticking out so you can pull it back out, tie a knot on the end for security.
- turn the piston to tdc untill you feel the resistance of the rope against the head, this will prevent the valves from falling down ;-)
- take out the buckets and springs for that cylinder, also described in the tsrm
Now you're looking at the stem seals.
Best is to use a special pair of plyers which have a 'O' shaped mouth to pull them out.
When you push the new ones on, you should feel a snap twice, then they're on properly. Make sure they're not on tilted.
Repeat for each cylinder.
It should take an unexperienced mechanic about a full day; there's quite some work before you can even take out the cams as you need to remove the distribution belt. One more tip; before removing and de-tensioning the distribution belt, put it into gear or 'P' when you're auto and loosen the cam gear bolts. Only just enough to loosen them not more, saves some hassle later on ;-)
Good luck.