Here are some old photos that show the condition in my 1966 Express, which I found to be quite odd. Literature of the day indicated the side structure on each side of the after section of the helm station was aluminum, but in reality there are steel channels that have "US STEEL" stamped on them, and then they just kind of stop in mid air with NO SUPPORT under them.
Perhaps my boat used wood support that rotted away? In any case, here is the photo documentation
photo of rotted steel exhaust collector, note the unsupported steel structure
Another view, showing part of the motor for location reference
You'll note in these crude photos, the structure terminates with what looks like a base plate, but there is nothing underneath. I took treated wood and nested it under these base plates, and snugged them with long slender wedges I cut on a table saw, all secured with 3M 5200. The result now, is the steel base plates can transfer some of the downward weight onto the fiberglass hull structure. Without this support, there was a degree of flex upstairs that was unacceptable.
The aluminum windshield box sections on each side of the front windshield are side fastened with large bolts at various points on my 1966. Its an express, perhaps the sedan flybridge used a different method. I tried to remove and refasten some of these, and they were so secure I could not remove them without destroying them, so I left those fasteners in place.
My headliner was out during this phase of the work, and I reinforced the express rooftop with laminations of marine plywood and 5200, in order to take the spring out of the roof. My boat has an aftermarket flybridge.
Here is a photo I'm adding with an edit. It shows how the front aluminum tube is held in place (on an Express). I would have to assume these are bolted and not threaded to the aluminum. They would provide plenty of shear resistance, but would in my opinion need to be bolted in order to not work loose over time.
Regards, Paul Pletcher
1966 38 Commander Express
Original 427 power