With the case removed, measure from the center of the output shaft to the inside of the body. This will give you an idea beforehand of any interference you may encounter when installing the new Atlas and also give you an idea of whether you will need to clock the new case. Now is also a good time to determine where the twin-stick shifters will be positioned and how the floorpan will have to be modified to make room for the shifters to have a full range of motion. Advance Adapters does suggest the use of a 1-inch body lift when installing an Atlas, but we were already as high as we needed to go in terms of lift. Thus we cut up our floor a little more than if we had gone with the body lift.