White smoke coming out of my tailpipe!?!!

SOURCE: transmission fluid going through engine.

It very hard to give an accurate diagnosis of the problem if you don't state at least the year of the vehicle because technology on cars change every couple of years, and a component that is on a vehicle this year, might not be on that model next year.
Here's a guess: if your truck is an older model, then it has a vacuum modulator on the side of the transmission. Often when these modulators go bad, the internal rubber diaphram ruptures and allows the engine to **** up transmission fluid.

SOURCE: I had my distributor replaced

sounds like your timimg is off either by a tooth or at least a few degrees, does it make a rattling sound when you come on to the fuel hard? Also check to see if your coolant level is going down if so you could have a bad head gasket.

SOURCE: 1993 GMC SAFARI WHITE CLOUD OF SMOKE COMING FROM THE TAIL PIPE

usually when your exhaust shoots out white or grayish white smoke your head gasket is out. its not a hard or very expensive fix.

SOURCE: 1988 gmc 1500 Gas smell coming from tail pipes

running rich?. make sure your air cleaner is clean the filter is clean. how old are plugs, wires, cap, rotor, o2 sensors? also you feul injectors could be leaking extra feul into the engine. run the engine with the air cleaner off. let it warm up. shut off. look at the injectors with a light to see if they are leaking. does it burn alittle on whenb you first start it?

SOURCE: white smoke when reved up

White smoke on startup could be a head gasket leak between the water jacket and the cylinder. Won't always show in the oil. Antifreeze makes it smell oily or sweet. Compression test will tell for sure. Bluish is oil that was burned. White is usually water or oil into exhaust after combustion.