F3WMB, IIRC it was 750KIAS Vno when I first started on the jet and then it was dropped to 725KIAS as there was no Vne. I also met the boffin that designed the intake during a visit to the squadron by some of the factory staff. He said that they had limited the aircraft Vne due to the intake design as it hadn't been tested any faster - he claimed it being capable of much more than the imposed Vne (and he was right as many proved
).
Yes, the old HUD switch between IAS and Mach caught many out over the Nevada desert floor at ~6,000ft up. You could be doing 690kts near the ground at 250ft and be supersonic! That little chestnut did for a Winnebago on a desert road in the exercise training area when a F3 went over the top at ~720kts. Just don't ask how I know!
LJ