Has anyone here replaced the power antenna? I have found a few on ebay and was wondering if it is a big deal to replace it. Any thoughts would be appreciated.

On late 79s-82 it's pretty easy. The chrome bezel holds the top to the fender and a simple bracket secures the bottom. Some GM replacements have a short pigtail with a plug on it but some original installations don't have the connecter, you need to run the cable all the way to the relay or splice the wires. A pair of needle nose pliers works to unscrew that original bezel with the slots. It doesn't need to be real tight, after all, it rests right on the paint. The early 79 and earlier antennas almost always require muffler removal to get at them because of the way they mount but yours should be accessable with the mufflers in place.

My opinion, stay away from the aftermarket antennas that are all over ebay. Occasionally someone on ebay has a correct GM available. Several of the Corvette venders offer a accurate reproduction for the later C3s, about $180.

Have you considered repairing your original? Usually a broken nylon leader that raises and lowers it. If the motor runs and the mast sections are not bent that may be your best bet. I'm helping a guy on another site right now with a rebuild. Sending him 2 nice mast sections as his were bent. My LAST antenna spare parts.

I got mine from Ecklers.  You do have to run the wires up (red {hot} and antenna lead) to the front.  I ran mine thru the wire loom under the sill plate and behind the kick panel.

I have the Super Tuner II so I was able to hook the wire up to the remote lead.  You need to find a hot wire that is hot only when the radio is on.  Use a tester to find the wire you need.

The best advice I can give you is to take your time.  Mike is right.  Don't tighten the attach nut thru the fender as you can crack your glass.  He is also right that you might be able to fix it with one of the kits that Ecklers, Mid America and others sell.