If your axles are too short, then you will have to make your own thrust pin if you want to keep on using the Timken bearings but many will just go with the Green Bearings (ball bearings) and not worry about the thrust pin. Also, there's so much tolerance in the housing that you have to pay attention to what the widths are vs axles. Don't know about the 'A' body rears but I've run across B rears that vary from the same model car. I've had some that were 1/8" to the side shorter. That's a 1/4" total. If you pick up a short housing and then find some axles that are a tad long....well, the tolerance can stack up on ya. Measuring to the decimal point is......usually pointless. :D