kelsey hayes brakes

i found a car that has the kelsey hayes 4 piston brakes i am wanting to buy for my 67 dart , the guy says they have new ball joints , a frame bushings i cant tell they are new and would probably replace them any way . he wants 300 dollars for everything complete including the power brake booster and all hard ware . my question is , is the a frames the same between the drum brakes and the disc , is the lower control arm the same, can you get all the parts to refurbish them ( brake pads , wheel bearings , ball joints, a frame bushings, calipers, brake lines etc.) and if so where can you get these parts at.
thanks for any help
dewayne henderson