I run them open on my Challenger so that I can get as much cooling as possible, and I also do not have the insulating pad, so no worrys of the belt problem.
Also I normally do not drive it in the rain, but a couple of weeks ago I was taking it to a friends house and got stuck in a bad rain storm for about 15 minutes. When I got the chance, I opened the hood to see how wet everything got and to my surprise, it was almost completely dry.
I doubt I will ever put the aluminum plates back in.
pink440,
I doubt that removing the plates will help cool that 440 because that is a bunch of motor, but you could try. It won't hurt, unless you drop one of them on your paint job. But like the others said, you would also need to remove the insulating pad.
Good Luck.