I recently installed a "shift point kit" in my THM 350 tranny, trying to get it to shift at ~5000 RPM at WOT instead of 4000. The kit includes new springs and weights for the governor. Well, the result is that I have to manually shift the tranny or it will never downshift from 3rd gear. So, I was going to take out the governor, re-install the factory weights and springs, and hopefully get things back to normal. Problem is, the governor does not seem to want to pull right out, like it did when I installed the kit. I have a suspicion that the gear is stripped and therefore keeping it from sliding out easily. Any ideas on the situation and how to get the governor out? Any advise would be much appreciated! Thanks!

I hate it when that happens!
You can use a screwdriver to gently pry on it, while turning the driveshaft. The problem with Corvettes is, it's really hard to turn the shaft with the driveshaft connected.
Try to pull it out with a screwdriver, remembering to twist it at the same time. I have rarely seen one that needed to be "persuaded" with a hammer, but it has happened.
The problem could be the gear has damage, but, most likely the shaft of the gov. has gotten galleded to the case of the trans. This is not really a big issue, tho, unless it has damaged the case.
If in fact the gear is damaged, and the gov is hard to remove/install, here's a tip...
Once you have the gov out, get a brake cylinder hone( a ball type, or "dingleberry" hone), and put it in a drill. Run the hone thru the gov hole in the case, to remove any high spots/grooves. Then, reinstall the gov COVER only. Once the cover is on, start the car, and put it in reverse. This will flush any poop out of the gov circuit back there.
Then, reinstall the gov, and cover, and see do it werk properly now.
Let us know how it werks for ya. Adams' Apple38902.4330208333

Thanks Joel, I'll give it a try.  It will pull out just a little and it will also twist a little, but then it just won't come any further.  I pulled with some vise grips, but didn't want to pull so hard that I broke something.  Am I in a situation where I just have to pull as hard as it takes to get it out, then see whether I have damaged anything?

Also, if this is a gear problem, can I assume that the gear in the trany is much harder than the gear on the governor, specifically so the damage would be localized to the easier-to-replace governor gear?

The "gear" in the trans is actually machined into the output shaft. It is very hard to mess it up!
If it is that hard to get out, there is some sort of damage, anyway, so I wouldn't worry about making it any worse. The most you would have to do is remove the tailhousing to fix anything. I think you'll be able to "jiggle" it out with a large screwdriver. Even if the gear is damaged, it is made of nylon, and the worse you can do is break the end of it off. No big deal if it's already chewed up anyway!
If you need a gear, or a complete gov. let me know, and I can send you one.
Check out THIS pic to help, maybe...