[a2tripp]

The problem is the worst when the temps are in the 40's and during morning warmup. You can take a blow dryer and blow it in the intake and it will clear up instantly.
This is very annoying because you have to feather the throttle until the motor completely warms or it will die in gear or on the brakes. This requires 10-15 minutes time/ gas to deal with it. Others here have the same problem and they deal with it or have some type of provision in the intake or exhaust manifolds. I have nothing on my manifolds, so fabricating something will be my last resort. To battle this on other motors (360amc and 360dodge)I used a suggestion from a friend to use a cut up coffee can and aluminum foil. This works ok, but creates rattles, and will rust out every year. Actual ice will not build up unless I am farther up north at highway speeds. blocking the radiator with cardboard works great in that situation.
Moisture on the element also contributes, but the problem is still there with a new filter.
silicia (sp) from shoe boxes, those little packages are no help.
If there was a heat valve after the manifold its long gone now, in the past though these have not helped.
I like the idea of a plate blocking the fan, I thought about taking the fan off and seeing how it does but the po super riveted the shroud on.
I live in what seems the rainiest part of the world, it rains over 13ft/ year and we have not had a sunny day in over 2 months.
I really appreciate the suggestions, other than ditching the carter carb and going to a holley or efi i might be sol. I have to believe that someone sales a solution to this, in a box that can be delivered, looks half way decent, and be corrosion resistant.
Thanks again and sorry about the long post. I drive my truck as much as possible and am proud of how well she runs, but warming up in the morning wakes the kid and wife, not to mention my rotton neighbors.