I just can’t figure out why some pay extra for an HP stamp. It’s just an hourly workers job to designate that the internals are HP. All the blocks in any given year are pretty much the same.I think it was a replacement crank, it could have been the "cheaper" way to go at the time for the previous owner. It was 35 years ago when I got it. Its still the same. The block is "HP" for sure. and the rods look super strong, it just has to be externally balanced. ( I would sell this complete motor)