$600 bux. You can do it in your garage with the car on stands in a weekend or a long day. It's a straight forward job. Do not try to be neet by removing the radiator drain plug (stock drain plugs may twist out the bottom of your radiator!), just pull the bottom hose or be very careful!
a few more tips:
Remove the hood (but it can be done with it on).
Remove the heat shields after you remove the valve covers (shields may scratch the painted covers).
Valve cover gaskets are re-usable.
Good time to swap the t-stat and hoses (the t-stat is a pain to do with the intake on later).
Early '94s (4 stripe manifolds) may have a hidden bolt holding the fuel line just in front of the crossover.
One of the bracket bolts on the front passenger side head may bind and strip a few threads (be ready to chase the hole with a fresh tap if necessary). Two of the ones I've done had this problem.
Can't remember which years.
I use a shop vac to draw as much fluid out of the heads/block as possible (after draining of course) to minimize splliage onto the pistons before I remove the heads.
Have another look at the comments made by others here. There are plenty of posts on this subject......
Enjoy