Richard Lederer in the Nov 1997 Word Ways mentioned words which become other words when their terminal letters are interchanged (the first and the last letter are swapped), as SWINDLES to SWINDLED. He gave seven examples of four-letter pairs, five examples of the "rarer" five-letter pairs, and three examples of six-letter "prize" pairs, given them the title "simultaneous loopers" since the two letters are looped to the other end of the word at the same time.
"Swapping Terminal Letters,"
Word Ways: Vol. 32
, Article 4.
Available at: http://digitalcommons.butler.edu/wordways/vol32/iss4/4