When I took my Holley NH carb apart, I had to heat the carb to remove the needle valve seat, which is common from reading the forum. I have heard that it is necessary to remove the gasket for the seat. Is it possible that mine didn't have a gasket? There is a rusty like crust on the seat and testing with an awl makes me believe there is no gasket still in the carb base.
Question two, a new needle valve, when screwed into the carb base without the seat in place or the lock cap nut, is a little wobbly. Should I be concern and what can I do?
You may need to use a spot facer to smooth the area where the gasket goes under the main jet. If it does not seal properly fuel will not be drawn evenly.
The needle valve being wobbly in the threads without the clamp nut installed is normal and of no concern.