I wanted to bring this thread back up. There are a few things that might help guys out.

Some of the carbs I've bought were completely stuck. A propane torch and PB Blaster can help remove some really stubborn screws, idle mixture screws, and loosen the throttle shafts.
Heat the area around the stuck screw or shaft, then shoot the area with the Blaster. Apply more heat until the area is smoking again, you might see the Blaster bubbling up which is great, shoot it with more Blaster. It may take 5 or 6 tries but eventually you should be able to remove anything. Be patient, don't force the screw or it will just break off. The Blaster will flame up but nothing scary. Work in a well ventilated, open area away from things that can burn.

Finally worked with the choke pull-off adjustment enough at the track that the carb doesn't bog anymore. The car has run 13.90 @ 101MPH at our local track, and 14.12 @ 99MPH during the Pure Stock Muscle Car Drags.