Vintage Cars: 67 beaumont, 67 beaumont, mechanical work

Question
how do i change standard steering and brakes to power big bucks?

Answer
yes it can be done, not an easy DIY job unless you are versed in how to do major mechanical work and yes fairly expensive job. You would need to replace all brakes lines and install booster, PS requires pump, and new steering components.  Best way is to find parts car with that feature and remove and put on yours.  If that was not an option for your car and that year, you would have to go to aftermarket which you require major modifications and $$$
Good Luck
Ron