help!!

[old Rusty C10]

got up this morning to find a flat on my ranger and didnt feel like messing with it besides the kids had to get to summer school so i hopped into the chevy for those of you who dont know its an 86 C10 with a 4.3. and a turbo 400 trans; this truck originally had a bad motor but i got a used motor from the junkyard that was in a monte carlo and converted it from an EFI to a carbuerated model also because i had to use the old setup from the original motor ( intake manifold, carb and distributor) and it was racing like an SOB, i had the q jet rebuilt and that was installed yesterday. According to the rebuilder the q jet i had was full of junk from the original motor and the secondaries weren't opening or closing right causing my racing problem)
Well about four miles down the road it starts missin like it aint firing on all 6cylinders but the more gas i give it it keeps running til i stop for a lite then in just shut off. Fired it up and it ran til i put it in gear and then she died again finally after like ten tries i get her goin again and i get the kids to summer school ( damn flunkies are in summer school)
well i get like halfway back ( almost three miles) and the damn truck does it again. Same scenario finally get it goin and its barely moving, I pull into this gas station and this guy looks at it who is alledgedly a mechanic and he tells me the rotor is shot. At this point im thinking hes nuts and i dont have tools so i tell him to change it. Well it took three hours to get the damn rotor delivered to his shop and for it to be installed ( $20 later for a rotor U.S> no less and the truck fires up and runs ok i get out of his driveway and it starts missing slightly i said screw this im heading home
barely made it home it was missing alot, and when i tried flooring it it was like NO power took forever to shift into second etc
thought i heard one slight backfire out the exhaust and i did see black smoke sometimes
Anyone? i was thinking pickup coil or distributor?? but i dont want to throw bucks i dont have at this truck on crap shoots
by the way cap and rotor are new as are plugs and all filters
this truck has california emmissions and im not sure if all the vacuum is right i tried to remember what i could when i took the old motor out but a buddy came over and adjusted it and said it was cool the way he did it ( he is a retired dodge mechanic)
i called up a different mechanic friend and he said it could be a computer problem or a sensor too but he was saying that when i converted from a fuel injected monte carlo motor to a carbed motor i could have screwed the system up cause the motors are alledgedly difrferent,,, i called chevy and they told me that the mechanic who told me that " was doin drugs" the motors are virtually the same except for the intake system which is now changed over to the application i need as intake manifolds for carb and EFI are different as are the fuel feed systems and the distributor which was also changed over..... so in one word people..... HELLLLLLLPPPPP!!!!!!!!!!!!!!!!!!!!!!!!!
ps sorry for the length this is also a rant !!!