As theetruscan has said, I wouldn't likely worry too much about erosion of the block. However, you're going to need tubing better than regular Clearflex or Tygon (rated to 25-35psi) as well as a radiator suited to those high pressures (50m H2O ~ 70psi). The block shouldn't be a problem though... o-rings and solder joints will handle more pressure than the pump can produce... you'll have to watch the threaded connections though.
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Michael E. Robbins
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