I have several impellars. I searched this site to find my answer but no luck. I know that its common to find impellars that when re-cut are not usually re-stamped. My question is: How to ID an A from an AA in regards to what is stamped into the casting? Are the letters next to each other? I have some stamped A 2, A A but they dont sit next to each other. So are these A's or AA's ?