It was also used in a lot of the older displacement hall boats, like smaller commercial fishing boats and cruiser's, even used as twins on larger cruiser's. They were popular, more so then the V8 configuration because it allowed for a more compact setup so the stern didn't need to be as wide. This allowed for the hall to cut the water more efficiently and that was important for a displacement hall. There are a lot of 20-40yr old boats still being used at the coast, you just need to make a few phone call's, you'll find one.
