Some ram air hoods (esp ones with functional airboxes like Redraif's Suncoast RA1) have a rain deflector built in, just behind the opening, and a few drain holes for the excess water. I have never noticed any rainwater getting past the airfilter (K&N), since the oil repels it. My 97 SS filter was always getting wet until I put the K&N in it. It wasn't enough to do any damage, just enough wrinkle the filter a little.
1981 Corvette LSX/T56 Project
1987 Trans Am
1985 Trans Am
1997 Camaro SS #359 383 LT1 - Sold 8/12/09