I don't believe the 65 had one. Has anyone built one, or aftermarket? Looking for ideas!

The 65's that came equipped with a/c or 327 high po engine or heavy duty cooling did come with a fan shroud. It was basically a metal ring that was mounted with metal bracing bolted to the radiator. I have seen two types: one has a shallow ring, about 2 inches deep and the other is deeper, maybe three or four inches. I had the shallow one on my 65 but sold it when I switched to electric fans. They come up on e bay now and then. Another option is to use the plastic shroud from a 66/67 car which is available from repro vendors like OPG and Year One. They have to be modified slightly to fit, but I've seen a few of them and they look factory.