Factory backspace for 14x5.5 rally?

I have used a spacer on one wheel before. I tend to run big tires that barely fit. With the early A's and the 68 Dart the fenders are low. So I have used 1/4" spacer on one side to minimize rubbing on the inner fender. Quality is important when using a space has to be a solid piece of aluminum no voids from castings.