Chris,
I just did this on my 85 last month....
Getting the races out wasn't that difficult, but they didn't just pop out; I had to tap (firmly) a couple times on either side of the race, side-to-side to walk it down the bore.
Make sure that you have the hub on a solid surface to ensure that the energy you are exerting from the hammer isn't getting lost. I put mine on a the flat part of a heavy vise.
Honestly, the toughest part was seating the races....I learned the hard way - don't repeat my mistake.
Heat the hubs to around 300F for around 20-30 minutes in the oven after you clean them up....it won't smell very much.
Freeze the races for a couple hours prior to heating the hubs.
Look at the hubs and take note that the larger side race seat has a "false" seat under it that tripped me up - Jason set me straight on this thankfully. If you don't notice this, it will look like the race is not seated by about an 1/8".
The best way to verify the races are seated squarely on the seats is to use a dental mirror to look all the way around it - another Jason tip, he's a sage!
I'm not sure why you have to hit your races that hard, but I'm assuming since you have an 84 that your hubs will be the same as mine.
I posted pictures of my hubs/race seats in this thread:
http://forums.pelicanparts.com/porsche-911-technical-forum/852167-wheel-bearings-questions.html
Good luck,
Erik.