Hi Rob - I know you are a well informed person, but the hull form appears to be distinctly Uniflite. Do you suppose there was some collaboration or contract work done between the two firms in the late 70's, early 80's?
Not that I've heard of, but it's entirely possible there was. Some of CC's and Uniflite's designs were similar in styling in general though (which might be part of why Chris Craft absorbed the Uniflite models so easily).
The 380/381 hull is a bit of an oddity. The broken sheer line was definitely more common on Uniflite models than Chris Craft models (many of which had a straight sheer at that time). But Chris Craft had done boats with a broken sheer in the past, including the 35 Commander hull and the 35DC / 350 Catalina that evolved from that hull. The older 36 foot Commander sport fish had a broken sheer as well, and those were all definitely in house Chris Craft designs.
Where the hull gets weird is when you look at it out of the water. The underwater sections don't really look like a typical Chris Craft hull or a typical Uniflite hull, particularly in the convex forward sections and relatively prominent keel that cuts upward significantly towards the stern. There's also not a lot of deadrise at the transom (only 10*), the transom isn't deeply immersed for the size of the boat, and there's a small stub keel / rib that carries all the way back (similar to some of the earlier Commander hulls except the keel is a box rather than V shaped at the bottom).
The chines and sheer line on the 380/381 definitely do look similar to the Uniflite derived models, but comparing my boat to pictures of a 426 Catalina the chines on the Uniflite hull appear to exit the water a bit further forward (relative to the length of the hull), the Uniflite keel is much smaller and disappears entirely aft, and the Uniflite hull has more immersed transom and more deadrise aft. Many of the fiberglass Chris Craft hulls also have an additional step in the hull above the chine, normally a few inches above the waterline, where it notches out about an inch, almost like a double chine. The Uniflite hulls don't have that design feature.