Driving in the rain, car cuts off - HELP

[Viperlover]

Whenever I drive in a steady-hard rain the car will cut off when coming to a stop. Does it sound like the distributor is getting wet or humid to you guys?
I cranked it up and it was missing, and when you put it in gear it just cuts off, so now I'm stuck halfway down the driveway letting it sit. It was also steaming a bit but I believe it was just overflow out of the radiator as the temperature gauge wasn't hot and the top of the radiator wasn't very hot. At higher rpms it is fine, but when you slow down it will run rough.
Another thing to note is that it is the stock vaccum advance distributor on my 350.
Sound like I need a new one? I don't wanna just throw parts at it without getting some more opinions on it.
Thanks in advance,
-Shaun