One of the top speed SCTA racers at El Mirage dry lake told me years ago that anyone can run 125.MPH, a lot of guys can run 150 MPH
But to get the same car that runs 150 MPH to run 175 MPH you will need to either double the HP or slick up the car and chassis to reduce the wind drag.
I seem to remember him saying about 5% reduction in drag would do that for you on that car in his example, a full size door car, not a roadster or lakester