I am looking for some general ideas where to market a make specific car forum?
It is not practical to advertise on other car forums because of the competition factor, so I've been looking for some complimentary sites. However, the only thing I can think of would be parts dealers.
Try to get a lot of content first, such as posts, and then you can start to get search engine traffic coming. I would also go to some car shows and hand out flyers, or specialist car clubs. They would probably be very interested.