BigAl88

Hi, guys. I have a 1990 Chevy 3/4 Ton. Its got a 350 with a 400 trans. I'm having trouble with it running when it gets up to temp. I just replaced the timing chain and got the timing adjusted correctly. I took it up town and when it got to temp it sputtered and started blowing black smoke and died. I tried starting it agian and all it would do is sputter. I've replace the coil, wires, plugs, ignition module, cap, and rotor. It has fuel, and spark, and of course air, i just don't know what else is causing it to do this. Maybe the O2 sensor? Its a single wire O2. I checked the timing several times when it was hot and cold and it was correct every time. Even after it started having problems. Any help is appreciated. Thanks in advance.