From what I remember the "487" and "487x" heads are fairly sought after by lower end circle track racers. I know when I raced in a Street Stock class they were the most commonly used head out there. The guys who ran them paid pretty good money, so they must be one of the better GM castings *Bowties, and Vortec" were illegal. I never did come across a set while I was in that class, so I can't tell you from experience though. We always ran 305HO heads.