Don't take him to the dog park. Let him see the dogs and get calm before going in there. If he pulls and barks it means he isn't ready to meet the other dogs. What you need to do is test him in controlled situations...a dog park is not controlled, you can't expect the other dog owners to meet you and your dog's needs and keep their dogs leashed and under control while you deal with your dog's issues.
Barking can easily be misconstrued by the owners and their dogs. Owners will get nervous, their dogs will get nervous, and problems will start. It doesn't sound like you know how your dog would react to a dog in his face/close to him, but from a distance he barks. Until you know how your dog will react to other dogs, you shouldn't endanger other dogs at the park because YOU want to socialize your dog. Get a group of friends together, or go to training classes where your dog can meet dogs in a much more controlled environment.