I recently got my dream car, a gorgeous baby blue '83 and love it dearly. I got a white soft vinyl tonneau for it, and all was well until I actually tried to attach the cover. The front rail of the tonneau is supposse to slide in to the trim around the rear window...but then the trim pops off because the tension is too great. I've replaced the little plastic clips that hold the trim to the car, but every time I put the tonneau on it pops out again. What's the best way to attach the trim so I can actually use my tonneau cover?

The front rail should not be attached to the window trim, it will not hold a good tight cover. Move the rail down below the window molding and screw it into the front of the bed, be sure to seal the screws with rtv or better yet seam sealer.

5th gen elkys don't lend themselves well to a soft cover. There are some options and if you do a search on tonneau covers there's many post that should help.

Some of the 5th gen guys will probably speak up here with some info too.

I know a lot of owners dislike toppers, but I love mine. It's color- matched to the body I think it looks great. No window leaks, no rust in the bed or storage area. Can lock my kaddy cart and golf clubs in the topper. Also works great to haul my paintings back and forth to art galleries securely and weather safe. Can't imagine anyone who has had one not liking them unless they had an ugly thing. This is my third Elky with this topper. Sorry if this is a little off the topic but we are talking bed covers and i'm sticking up for toppers. LOL
Check out the photo in my profile. Doug

Many thanks, I will give that a try!