http://www.web-birds.com/8th/56/61st/61st_squadron.htm
http://www.web-birds.com/8th/56/62nd/62nd_squadron.htm
http://www.web-birds.com/8th/56/63rd/63rd_squadron.htm
Look out for the Johnson clan.
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EDIT: Nigel that is interesting, if 56th FG had changed to P-51 what would the end result have been? Seeing as most P-51 were lost to ground fire (on the way home) and IIRC the 56th did a lot of ground attack work near the end of the war. The P-47 was better suited to ground attack and could absorb a LOT more punishment than the P-51.