Ok i'm not an expert be any means. i'm just learning how the choke works on the 4barrel stock carb on my 1985 chevy pickup. Ok so here is goes. The truck idles extremly high and the choke was off (this is the setup when i bought the truck) Now i'm getting sick of the k-chug k-chug when i turn off the car (it feels like i'm in the movie uncle buck) Now i believe the issue is the choke pull off. i went ahead and put the choke back the original location (Notch in the middle) and then noticed the chock pull off was not working due to worn out throughout the years. so i went to napa and bought a new one, installed and noticed something wierd. there are two slides that come out of the choke pull off (one for the 4barrel and one for the choke) i think i understand the point of the choke pull off (opens the choke when you start the truck and closes when the truck is shut off)  but no matter what position the choke pull off is in (fully extended or sucked all the way in) it will not move the steel levers because of the slides.

ok so after all of that my question is Do i have the wrong Choke Pull Off?

Am i correct that when the engine is started the choke pull off will open the choke to start the engine?

Am i correct that when the engine is turned off the choke pull off will dis-engage and close the choke which will stop my backfiring?  

Any carb is, choke closed to start, and choke open, when warm. 85 should have a Quadrajet with electric choke. As the internal spring is heated by electric current, it expands to push the choke-rod and open the choke. On the other side of carb is the fast idle warm-up cam, that has an adjustment screw to tune warm-up RPM's. It sounds like you have the linkage hooked-up wrong.  

When i look at the choke pull off from the top the left linkage is the 4barrel and the right linkage is the one connected to the choke  

The purpose of the pull off is to open the choke slightly after cold start up. The choke spring will be holding it closed to start but before the spring warms up, the pull off will open the choke slightly to give the engine some air. The pull off has no affect on the choke with a warm engine. It is most likely not related to your run on problem. That would be a base idle that is too high or some fast idle malfunction like JW mentioned. The connection to the secondary air door helps to control the opening of the door by holding it closed until there is a drop in manifold vacuum.