That's a Rochester Model B carb. You need to know that when it's time to get a rebuild kit. Also lots of info on the 'net about the Rochester including some YouTube videos.

If you have the factory assembly manual, you can see how the throttle and choke cables are connected - see section 6, sheet 5.01. If you don't have the manual, you should get one. Amazon and parts suppliers have them e.g. https://www.amazon.com/1947-1954-Chevrolet-Factory-Assembly-Manual/dp/B00BGB7FXC

Step on the gas pedal and pull the choke knob out. The cable will turn the fast idle cam. The choke should close as there is a spring which makes the fast idle cam and choke move together. You can poke the choke plate with your finger and it should open and spring back afterwards.

Since you have to close the choke with your finger, either the spring is broken or not installed properly or there is something else hindering the smooth movement of the choke.

Gord 🇨🇦
----
1954 1/2 ton 235 4 speed