Got the Blazer running....Stupid ass me. Figured out why it smoked, turns out the vacuum switch on the transfer case is bad and was pulling trans fluid in to the vacuum lines and the port is on No. 2 and 4 cylinders on the intake. Dumbass.
I got paid to take a Buick Regal once that had sort of the same problem. Vacuum modulator was bad and was sucking trans fluid in to the intake and it would smoke like a train.