Cloud of white smoke

I have a 1980 450 SL. When the car is cold after about 1 minute I get a very large cloud of white smoke for the exhaust. This lasts about a minute. If I restart the car when it is still warm I do not get any smoke. I am thinking that I have a bad transmission vacuum modulator. I think I can check it by removing the vacuum line that connects to the back on the intake manifold. If I disconnect the vacuum line and start the car and it does not smoke I would guess it must me the vacuum modulator. Any thoughts on the smoking problem? Will I have to remove the transmission to get at the vacuum modulator?

-Help