[Tommy]

I've driven my 63 Corvette with manual brakes since 1978 with no trouble stopping it. My Cobra stopped well from 140 MPH at the track with manual brakes. My Cheetah also has manual brakes and stops well with acceptable effort from this old driver. Something needs to change with your car's brakes. It could be pads or any of a number of other things. . . . To begin, I suggest you find a safe place where you can do an emergency stop from about 35 MPH. You should be able to lock up the front wheels before the rears. If you can't do that with acceptable pedal effort, or if the rears lock up first, come back and tell us more about your car.

P.S. If you are a DIY kind of guy, take the wheels off and inspect the brakes. Pay particular attention to any signs of fluid or glazing on the brake pads.