valve stem seals are not a nice job...very very tedious work..and yes u do need a special tool to take off the head to start with
http://www.bajanchameleon.com/rebuild_price_list.html
that gives kind of an idea of how its done.........the only part i hate about it is that its tedious (take a little while and very boring---not rocket science)
u need an overhead valve stem tool.........exactly like the one in the pic---its pretty cheap too....as they are others which are much bigger and not needed
just make sure u mark each shim when u remove it....like i always do....try wiping them off one at a time when u take them out....then use a permanent market to mark them....example I1, I2,I3, etc for intake........and E1, E2, E3, for exhaust........more than likely come from the timing cover side
the valve stem seals u will pry up with a bent screw driver...........and replace the new valve stem seals with a small socket CAREFULLY---they will kind of clip/snap on when in place---fell for it........or like wise u can use a piece of hose to puch them on...much easier to feel when they go on
u can put piece of wood or something soft into the chamber to keep the valves from falling
use grease on the tip of a very small screw-driver (value peck maybe) to replave the two small pieces of metal that hole everythinng in place
and pray a lot....as there may be some cursing involved...lol