Most vehicles don't have exactly the same track width front to rear. For example, WMS to WMS, should be within about 1/4 of an inch tolerance.
40/55: 55.7" FR, 55.6" RR
60/62: 58.9" FR, 58.3" RR
Narrow Front #J7#: 56.2" FR, 55.6" RR
80: 63.3" FR, 63.5" RR
The major difference in FR/RR track...