The S10 spindle is completely different height and design and will not fit the 64 -72 A-body, not without causing the same problems as the tall spindles. I believe Performance is casting a completely new spindles in the design of the original 64 - 72, but are making it work with s10/ 78 - 87 a/g body brakes. The brakes on the later model car is very inadaquate ask a Grand National owner, I had a Monte SS and the rotors warped constantly and the brake faded all the time, these brakes are a joke, and this is on a car that is approx 300 lb lighter. Don't use these brakes, use the OEM spindle and drop the car with good quality springs.