Black smoke coming out of the exhaust

Black smoke = excess fuel. Could be high fuel pressure, stuck open injector(s), fuel pressure regulator failure. I would start with a pressure test as a starting point.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

same vehicle that was running poorly throwing out black smoke now has
overheated and wont start. fluids are good. is it the head ?

Without testing it could be a variety of things. Did the black smoke issue get repaired before the overheating or did it just run that way until it died? If the coolant level is OK then it either has a water pump issue, the fan failed or there is an internal engine failure like a head gasket.

Does it turn over but not run or???

It went from running good to crappy throwing out black coffe grind exhaust.Then
2 wks later quit running and will turn over but not start. wouldn't a water pump
be leaking ?

Not if the impeller failed. It just wouldn't move the water.
Was it just black smoke or actual grit and pieces? If it was that it could be that the converter(s) failed and are plugged up. That would also cause it to overheat because the exhaust would be blocked.

Run a back pressure test on the system. A quick method to see if it is blocked is to disconnect the exhaust at the manifolds and see if it runs better.
https://www.2carpros.com/articles/how-to-test-a-catalytic-converter

this vehicle passed emissions 2 weeks prior to its down turn and was in the bottom
%30 of carbons ect. its's a v6 and I had rebuilt just the bad side of the head myself 3 yrs ago
there is no fluids where they don't belong. pulled the radiator cap off and cranked it and no radiator fluid shot out. with it going through emissions so easy could it still be the exhaust ? thanks for helping me steve

or converter

It all depends on what failed and when. Coolant and excess fuel into the system could easily plug it up fast. I would start there and work my way back to the engine. Black smoke is pretty much always excess fuel through the engine. That can kill a converter quick and the converter could cause overheating. The hard part is knowing if it's worth repairing that engine or just putting in a replacement. That all depends on what you find with the fuel and exhaust systems.

thanks for your help steve. 1 more question. could it be a plug
not firing ? I bought new wire"s and plugs thinking that....maybe

One plug missing wouldn't cause it to be this bad.