Up for buy-It-Now is a nice valve guide installer tool, Kent Moore part number J-3887.  This item was obtained from an old service garage and is not a newly remanufactured part.  According to my Kent Moore Manual, this is used on the following models and years:

1950-1953 GMC Truck..w/ 318
1940's-1953 GMC Truck..w/ 360, 426, 477 & 503

  This most likely is used on newer models, but my parts lists ends at 1953.  Please refer to your own individual manuals for newer models.    the tool is in excellent used condition and is free of any damage.  The installation end shows very little indication of wear.  Cast on the piece is Kent-Moore USA , J-3887, REPL. VALVE GUIDE.
  Please feel free to E-mail me questions.  International bidders are always welcome.  Thanks for looking!!