Not sure how a 240 stacks up against a 1963 190dc, but in general you just have to commit the engine to full output most of the time. Downhill excess speed is just an investment in the next uphill. There is no mentum like mo mentum. On a flat that car would do 65-70, flat out, after about 5 minutes of acceleration, with a tailwind.

Marginal power is kind of fun because it really makes you aware of subtle changes in road grade that would go unnoticed in a more powerful car, like a 617. And you really feel like you are getting your money's worth with the pedal on the floor all the time. I mean, who gets to drive a car like that in normal traffic? Fast cars are such a waste on public roads.