Not sure if I'm in the right area but I need ideas. I recently purchased a factory GN spoiler for my 83 Regal. I had to do some minor repairs and one was to remove the mounting studs and replace. I used 5/16 stainless bolts. Now my problem is I drilled out my trunk and of course the initial holes were off a little from the spoiler so I had to open them up a bit to get the spoiler to sit right. My problem is the original rubber washer I intended in using is too small to cover the holes now. I was thinking on using a larger rubber fender washer but not sure if that will give me a water tight seal. Anybody have any other ideas because the last thing I want is water getting in my trunk. Thanks