More than 140.
I pretty much maxed my tuned FTO when it was superlow and derestricted. It went well past 150 on the dial, I think touching 160 briefly. It was an amazingly calm experience, which I put down to the fact it was barely more than 4 inch off the floor at the time.
It's not the fastest I've been, but that was a very recent event, and it was nowhere near as calm, even though the car being driven was technically much more capable.
I'm looking forward to putting my 'new' '68 Mercury down the strip. It won't be 'fast' (gearing tops out at 115) but it'll get there like a scalded cat. My old '62 Corvette should be a rapid cruiser when finished with it's tall gearing theoretically letting it run to 175mph, but even with 400hp+ I expect it to be nervous at anything more than 120mph.