[Coley]

Ok, a few things:
-Within a few seconds of your engine firing upon start-up, vacuum is developed which should pull the choke (choke plate) open, via the choke pull-off... to its initial (very) cold run position.
This opening process has to be adequate to run a completely cold engine and will provide a more rich mixture. It would probably be cracked open initially about 1/4" or thereabouts.
-As Geezer said, as the engine warms up the choke rod will continue to open that choke plate so that after 15 minutes the choke plate should be pretty much vertical.
-Also, make sure that the horizontal small (hollow) tube that sticks out right underneath the choke-pull off leakage is plugged when running or connected to the air cleaner hose....do not leave it open or it is a vacuum leak.
-You can always 're-test' this manually if you want....when you go to cold start the truck, simply set a large shank screwdriver into the choke plate area to keep it open at least 1/4".
Then give the carb a couple of pumps and start it up....and check for a difference in the way it runs.
If it is/was the choke being held closed to nearly closed.....then you will see an immediate difference in the cold start result and it should be running with way less smoke.
If there is not change....your carb may not be the whole problem...but let's start there.

all good
Coley