I have a 72 gmc truck with a 350 engine and I see white smoke coming out of only one of my talepipe , I've tried adjusting my valves but no luck and also when I turn of the truck you can still see smoke coming out while it's off. So if anyone could answer this please do. I'm thinking it might be the head gasket no good because there is no sign of water in the oil

Thsnk you all who answer

You are obviously leaking oil from somewhere. The head gasket sounds like it needs changed.

White smoke is coolant burning,
Blue smoke is oil burning,
Black smoke is unburt fuel.
Still "smoking" after the engine is off? The residual coolant that is trapped in the hot exhaust is still "cooking off."
The head gasket may have failed between the coolant passages and the combustion chamber, and not leaking into the oil.
Have this diagnosed by a local qualified shop to determine what has actually happened and potential costs.