Looks like this motor lost its road draft tube in earlier days. If you have one or more information (pictures?) I would love to hear from you. Also is this tube usually fitted with a filter?
The early 65 and 64 1/2 289 had a road-draft tube that bolted to the rear of the intake manifold. There is a wire mesh filter (screen) inside the intake manifold, near mounting surface of the tube. These engines have valve covers with no pvc systems. The end of the tube extends below the engine and there is a tab that bolts to one trans. bolt. Try 978-948-2938 (MASS)days 11-7 EST, they have parted out a lot of early mustangs. He might have one.
Appreciate the response. Wire screen was completely gunked out so we filled the filter cone (?) with coarse steel wool. Tube is missing and I will try your contact number. Must be a few million that were crushed over the years. Only savage gent on the internet wanted what seemed a bit much....
Interesting thing is the passenger valve cover has a tube that goes into the carb spacer plate and vents blowby into intake air. The driver side just has the black oil filler cap.