I'm trying to remember the name of a movie that I think came out either in the late 70's or 80's. It's a post-apocalyptic movie about 2 friends whose parents locked them in a huge underground bunker as toddlers for something like 10 years. I don't remember whether they break out or if a timer unlocks the blast doors, but they were left with an old convertible that they end up driving around the wastelands in, dealing with scavengers and whatnot. I believe they end up finding their fathers at one point too.

I've searched imdb and all of the post-apocalyptic movie websites I could find and can't seem to find anything that rings a bell. So H/A, I turn to you.