If you are going to shorten the rear end as stated above the best way to find the rear length is to get the wheel / tire combination that you are going to use. Again the back space is a something to look at as less back space makes it easier to remove the wheel , also a deeper set wheel looks better imo . Maybe you have a friend that has a wheel tire combination that you could borrow to see what might fit. It is harder to figure the tire wheel out than the rest. It could be very costly if you make the wrong decision .Most vendors will not take a rim or tire back once it has been mounted. Also keep in mind to do any of this the rear must be removed.