Building a gasser

U mean to move the rear leafs in rite I put a 9 inch in it fyi 9 in ford axle housing out of a 59 ford fairlane is a direct bolt on 65 valiant
Doesn't matter who made the rear axle . If you want to get big tires under the car moving the springs under the frame rails is necessary . Even larger tires can be used by moving the frame rails inboard but that's major surgery .