Now the windshield frame is finally tacked in place. It's close to the marks I had before working on the defrost vents, so I am happy I did not distort the frame. I still looks square (the photo was taken slightly off the vehicle center line), so I am ready to start on attaching the roof from the 58 Chevy.
It's been a while since I've posted an update. I've been working on defrost vents to go in before I fix the windshield frame in place. Here's some photos of the vents attached to the windshield frame. I bent some 1 1/4 inch tubing to a series of 90 degree angles and cut the bent pieces to fit. The vents housings are fabricated from the internal braces I removed from the 2001 Malibu door frames. I cut them to the desired lengths and welded some 18 gauge pieces to the ends of each vent housing.
I cut the sides of the Del Ray roof just above the drip rail and laid it across the Malibu roof edges for a test fit. Left a little overhang on the windshield for the visor effect. The roof is back off and to the side now, pending addition of some ribs across the open span between the roof edges and some more work on the windshield frame to correct a high spot and two dips on the passenger side.
Got the driver's side roof edge tacked in place today. Placed the windshield frame in place with the universal attachment device - duct tape.
The fit is really good for a first-time guess. If the 55 Chevy windshield was another inch wide, it would be perfect. I should be able to bend the Malibu roof edge into the windshield frame enough to make it acceptable.