I know this is a really old thread but he has that car running in the 12's now at a track that is at 5,800 feet above sea-level. It is pretty awesome to see a car that big go that quick.
I saw that in Car Craft as well, very nice Duster. I always wondered how smoothies would look on a Duster and Steve's Duster answered that question. Who is the Denny guy that was mentioned many times in the article?
Here is a link to a thread about the article I mentioned in the post after this post.
http://www.forabodiesonly.com/mopar/showthread.php?p=1588134#post1588134
Glad you kept it wheels down.
There should be people that can give good advice, I know people who race in the stock eliminator class make good power out of a "stock" engine.
In the latest Car Craft I received there was an article about a Duster with a slant six and a turbo on it. I think it is an article that would help you.