Er, what car? In general, you have to remove the head. To do so disturbs a
bunch of stuff and it's a decent bit of work. You can lurk around at
www.vfaq.com to see what's involved. This site is specific to the 4G63 motor
but there all fairly similar.

It's a big job in any car. Some are worse than others.

With the head removed, have it checked with a steel edged ruler if there is
any difference, chances are you will have to have it machined, your first
expense. Second expense is the new head gasket and several other parts you
will need, here in Australia, a 1986 magna cost me 225.00 to get back on the
road again. Over there i really dont know, best bet is to phone around and
compare the costs.

Good luck

Peter