Just a note for the next time you clean the choke disc assembly, you don't need to disassemble it, unless you are replacing the o-ring on the shaft .
The thin brass plate on the back side of the disc, is spring loaded, you can get it about an eighth on an inch from the aluminum part and make sure the holes in the aluminum disc are open .
Did you make any note or take any pictures of the position of the brass shaft that the two part arm assembly is secured to, as Monte has mentioned, there is a dot from a center punch on the end of the shaft it needs to be in the correct position .
If you can get to the carb, where is the dot located when the choke is off ?
If the gasket doesn't help the situation, you may need to disassemble the choke assembly and rotate it 180 degrees and reassemble it .
I just rebuilt both carbs on my '82 LS last week and I took a few pictures before disassembling the chokes, I deleted them two days ago !!!!!