Here is a historic data point for you.
In 1985 I ran a friend's quite new Mark 3 Le Mans in a Bears speed trial. It was timed both ways over a flying quarter. Average speed 130.65 mph. I was 3rd on the day, first place went to another friend on his BMW K100RS at around 135mph. 2nd place was a very highly tuned Triumph with an average speed of about 0.25mph higher than the LM. A good fart would have done it!
I'm pretty sure it was maxxed out, the engine was quiet, there was just the wind noise. I had used my first run to figure out how to launch it and fit myself in behind the screen. And to crib an extra bit of run up at the starting end because that end was a bit shorter.