We need to think through the structure of the forum and any sub-forums. (The way I understand Nabble's sub-forum idea they would be like Engines, Interior, Tires, etc. But, there's a good discussion of that here.)
Man, oh MAN! What I would give for the ability to create a bulleted list with indentions right now!!!! But the way I'm thinking is we would have something like:
Engines:
300 Six
Windsor (265?, 302, & 351W)
335 Series
Diesel
385 Series
Transmissions:
Manual
Auto
Etc
But, we need to look around at other sites and see what we like of how they've done it.