A "typically" significantly lifted truck generally does not do well. A proper 4 link shouldn't matter what height (stock or otherwise) it's at as long as it was designed for it (one nice thing about a 4 link).
I would bet dollars to donuts that the custom 4 links are what won the competition for him. That suspension was well engineered and well built (kudos to the builder). It was a solid truck with good HP, but there were trucks with more. It seemed like every event he was able to get all his ponies to the ground which helps in trailer tow, trailer manuevering, drag racing, and sled pull (a majority of the points events). If it had been on stock lifted suspension, I don't think he would have faired as well.
He has an amazing truck and I would take it in a heartbeat and he did his homework, so not trying to dog it.
I believe his suspension was completely custom, not really indicative of what most Fords (and/or any truck with stock style suspension) would do. I would feel the same if it was a GM on 4 link front and rear too.