Re: Buying a New Carburetor
 

The later Quadrajet is slightly different, including a heavier casting. It's actually a better carb. Any place that's hot will work for the choke. You can tap into your IGN on the fuse block.

Re: Buying a New Carburetor
 

To power the electric choke all you do is connect a wire from an IGN UNFUSED terminal on the fuse panel to the electric choke's terminal. So it has power when the key is on. The choke electrical connector is available at the auto parts store or by googling "electric choke connector".

I think there are probably lots of differences between 72 and 81-85, but I don't know exactly what they are. There are more ports on the newer style carburetor because there were more vacuum accessories as the years went on. I bought a package of rubber plugs at the car parts store to block all those extra ports off, and bought a nylon threaded pipe plug from the hardware store for my unused power brake vacuum port.

I ordered the carb for a 69 truck online, and then followed up with a phone call to ask if they could outfit it with electric choke. The sales guy seemed quite knowledgable and helpful and said they can't just add an electric choke to a carburetor that was designed with a divorced choke, and they had to build a different carburetor that was originally equipped with an electric choke, and they could put it together with the linkages that would work for 1969. They could probably do the same thing for your 72, if the throttle linkage needs to be different for your engine.