I pulley swapped my 1980 Murray riding mower to make it a racer. This is the first real speed test after completing the swap
EDIT 72223:
Sadly, the Murray's transmission couldn't handle the massive RPMs, first I lost reverse, then 1st and 2nd gear, and now it has seized up completely. It was a fun project, and it served me well.
I'll have to drop the deck on my White or Yard Machine and see how they can handle a pulley swap