Black Smoke

Hello to all my new B brohters. I am new to the B scene. I recently bought a 88 B2200 SE-5 132000. Its a straight little truck runs good but needs a little TLC. It seems to to have little black smoke issue. I have changed the plugs fuel filter checked the timimng, plug wires, cap and rotor and checked for vacuum leaks.. I ran sea foam through it. I'm thinking it might be a carb issue. My fuel milage is terrible 16 and 17. Any ideas what to do next? Thinking maybe a Weber carb, and how hard is it to convert to the Weber.

Here is a pic of my B

Swapping to a weber is pretty straight forward. An adapter plate mounts to the intake then the carb mounts to the adapter. Is it just when you first start the truck in the morning it smokes? Or after it sits a while or constantly while its running?

Smoke all the time, I checked the choke its open.

Can you do a compression test?
That might be next. Sounds like you've addressed the regular culprits.
A burnt valve or worn/broken rings, maybe a gasket leak but you'd probably end up with bubbling coolant and/or white smoke.
Though yes, oil burns blue but if it's mixed with plenty of poorly burnt gas (low compression) it can all just look black.
If you find a low cylinder you can do a wet compression check to see if it's the rings.
Add a teaspoon of oil to that cylinder and retest.
If it rises, it's the rings.
If you can't do a compression test pull plugs 1 by 1 and see if the smoke goes away.
Oh and check your oil level/condition, though you probably already have

I'll try the compression test tonight.

terrible fuel mileage, black smoke and a stock carb are an indication that the carb is running in limp mode. Check to make sure that all the sensors are nice, clean and working. This includes testing out the little green coolant temp sensor, the oxygen sensor, and the devices on the carb itself. When one of those dies then the computer will run rich, to protect the engine by preventing it from going too lean.

The easiest way to rectify this problem is to put a Weber carb on it and be done, as there are many many sensors on a stock carb and replacements (for most) are close to 3 digits in price.

Good point Emjay, i forget you guys have sensors and a computer that actually does something!
Too lean? Too lean is great, it'll protect the engine really well as it won't run jk.