i have an 83 z28 with the l69 v8.
everytime i run the car white smoke comes out from somewhere under the engine and smells like fumes. I believe the problem is either a crack in the exhaust manifold or the seals are bad. any idea how easy it would be for me to repair myself?

That's a tough and time consuming job for anyone, even with the right tools.

White smoke is usually the valve seals, but since you say its coming from under the car, you probably have an exhaust leak too.

dose it only smoke when you first start it up because if it dose you have bad valve seals if it smokes all the time you probly have other problems like bad oil rings something like that

i don't have the know how or tools to replace the exhaust manifold which is what i thought it was in the first place...
how much do you think a mechanic would charge to replace it?
and as for the valve seals would those be easy to replace?