Welcome to the Stovebolt forums.
You won't find a supplier specializing in only GMC trucks. There are many interchangable parts though.
Your engine is different if it's stock and your dash is different. There are many other little differences which have been discussed recently. Hit the little "search" link under "post a new topic" and "post a reply" and search for "GMC differences".
You have found a great resource here. Don't forget to check out the rest of the website.
