just did rear-end swap

(68 dart) just did a 7.25 to 8.75 swap. I noticed that with NO air in my air shocks the rear end will go ALL the way up possibly into the body of the car if I were to jack it up high enough, my question is, is this normal or do I need to get some better leaf springs? Im sure if the tires would have been on car they would have hit fender well.