Use
I use 159056 on almost all Kirby's. The new Kirby's I use 159056 to break in motor. When you rebuild sometimes too much pressure could hurt. I use 159056 belts until motor is broke in. Then I switch belts.
If you use new belts on old machines could snap belt lifter or pull on impellor of fan
You can but I wouldn't they snap usually when you try to install on brush roll or first time you turn vacuum on.
Les
