280SE 3.5 white smoke only while warming up

[jniven]

I recently purchased a 280SE 1971 3.5 coupe. During warm-up (not when cold or at operating temperature) the car blows lots of white smoke. This only happens if the car is being driven. If I let it warm up before driving the car, there is no smoke. The amount of white smoke is far beyond that from condensation forming in the exhaust. Indeed there is that much it is embarrassing. Any thoughts?