I do a lot of powder coating and restore old motorcycles for fun and profit. I use powder for almost everything but not on engines or carbs anymore. Here is my 2 cents on powder coating a quadrajet.
It can be done but the reason I quit doing it is the castings are way to porous. So no matter how much you clean and bake to out gass the part its never enough. When you cure the powder you will have tons of tiny bubbles from the hi temp curing process. The prep would also be a nightmare. powder is very thick and strong so you have to be very careful in clearance areas, every hole and orifice needs to be plugged. If you get powder in a thread hole then cure, it will be very hard to remove. I have snapped taps trying to remove powder from threaded holes.
A good powder with proper prep will stand up to oil and gas without leaving a mark. its just very unforgiving and not the best option on certain pieces. If the carb comes out bad you would need a special stripper like B15 or Rapid strip to remove it. Sand blasting or air craft stripper wont even touch powder.
A better cheaper and just as durable option is Cerakote. You spray it on with a regular spray gun and only requires a low temp over cure that won't cause out gassing and is not thick like powder coating. the chemical resistance is excellent and wont even come off even with paint stripper.
https://www.cerakoteguncoatings.com/resources/files/testing/ChemicalResist.pdf
